Thousands of people descended on central Caracas on Monday evening, some walking for miles from slums on the mountains surrounding the city, towards the presidential palace.
Protests erupted in the Venezuelan capital the day after President Nicolás Maduro claimed he had won.
The opposition has disputed Mr Maduro's declaration of victory as fraudulent, saying its candidate Edmundo González won convincingly with 73.2% of the vote.
As thousands of people demonstrated across Venezuela, opposition candidate Edmundo Gonzalez on Monday announced that his campaign has the proof it needs to show he won the country's disputed election whose victory electoral authorities handed to President Nicolas Maduro.
Gonzalez and opposition leader Maria Corina Machado told reporters they have obtained more than 70 per cent of tally sheets from Sunday's election, and they show Gonzalez with more than double Maduro's votes.
Both called on people, some of whom protested in the hours after Maduro was declared winner, to remain calm and invited them to gather peacefully at 11 am Tuesday to celebrate the results.
“I speak to you with the calmness of the truth,” Gonzalez said as dozens of supporters cheered outside campaign headquarters in the capital, Caracas.
“We have in our hands the tally sheets that demonstrate our categorical and mathematically irreversible victory.” Their announcement came after the National Electoral Council, which is loyal to Maduro's ruling Unites Socialist Party of Venezuela, officially declared him the winner, handing him his third six-year term.
In the capital, the protests were mostly peaceful, but when dozens of riot gear-clad national police officers blocked the caravan, a brawl broke.
Police used tear gas to disperse the protesters, some of whom threw stones and other objects at officers who had stationed themselves on a main avenue of an upper-class district.
A man fired a gun as the protesters moved through the city's financial district. No one suffered a gunshot wound.
The demonstrations followed an election that was among the most peaceful in recent memory, reflecting hopes that Venezuela could avoid bloodshed and end 25 years of single-party rule. The winner was to take control of an economy recovering from collapse and a population desperate for change.
“We have never been moved by hatred. On the contrary, we have always been victims of the powerful,” Maduro said in a nationally televised ceremony.
“An attempt is being made to impose a coup d'état in Venezuela again of a fascist and counterrevolutionary nature.”
“We already know this movie, and this time, there will be no kind of weakness,” he added, saying that Venezuela's “law will be respected.” Machado told reporters tally sheets show Maduro and Gonzalez received more than 2.7 million and roughly 6.2 million votes respectively.
“A free people is one that is respected, and we are going to fight for our freedom,” Gonzalez said. “Dear friends, I understand your indignation, but our response from the democratic sectors is of calmness and firmness.” Venezuelans vote using electronic machines, which record votes and provide every voter a paper receipt that shows the candidate of their choice. Voters are supposed to deposit their receipt at ballot boxes before exiting the polls.
After polls close, each machine prints a tally sheet showing the candidates' names and the votes they received.
But the ruling party wields tight control over the voting system, both through a loyal five-member electoral council and a network of longtime local party coordinators who get near unrestricted access to voting centres. Those coordinators, some of whom are responsible for handing out government benefits including subsidised food, have blocked representatives of opposition parties from entering voting centres as allowed by law to witness the voting process, vote counting and, crucially, to obtain a copy of the machines' final tally sheet.
Electoral authorities had not yet released the tally sheets for each of the 30,000 voting machines as of Monday evening. The electoral body's website was down, and it remained unclear when the tallies would be available. The lack of tallies prompted an independent group of electoral observers and the European Union to publicly urge the entity to release them.
In the capital's impoverished Petare neighbourhood, people started walking and shouting against Maduro, and some masked young people tore down campaign posters of him hung on lampposts. Heavily armed security forces were standing just a few blocks away from the protest.
“He has to go. One way or another,” said MarÃa Arraez, a 27-year-old hairdresser, as she joined in the demonstration.
As the crowd marched through a different neighbourhood, it was cheered on by retirees and office workers who banged on pots and recorded the protest in a show of support. There were some shouts of “freedom” and expletives directed at Maduro.
Several foreign governments, including the US and the EU, held off recognising the election results.
After failing to oust Maduro during three rounds of demonstrations since 2014, the opposition put its faith in the ballot box.
The country sits atop the world's largest oil reserves and once boasted Latin America's most advanced economy. But after Maduro took the helm, it tumbled into a free fall marked by plummeting oil prices, widespread shortages of basic goods and hyperinflation of 130,000 per cent.
US oil sanctions sought to force Maduro from power after his 2018 reelection, which dozens of countries condemned as illegitimate. But the sanctions only accelerated the exodus of some 7.7 million Venezuelans who have fled their crisis-stricken nation.
Voters lined up as early as Saturday evening to cast ballots, boosting the opposition's hopes it was about to break Maduro's grip on power. The electoral council's results came as a shock to many who had celebrated, online and outside a few voting centres, what they believed was a landslide victory for Gonzalez.
Gabriel Boric, the leftist leader of Chile, called the results “difficult to believe,” while US Secretary of State Antony Blinken said Washington had “serious concerns” that the announced tally did not reflect the actual votes or the will of the people.
In response to criticism from other governments, Maduro's foreign affairs ministry announced it would recall its diplomatic personnel from seven countries in the Americas, including Panama, Argentina and Chile. Foreign Minister Yvan Gil asked the governments of those countries to do the same with their personnel in Venezuela.
He did not explain what would happen to the staff of Machado's, including her campaign manager, who have sheltered for months in the Argentinian embassy in Caracas after authorities issued arrest warrants against them.
Gonzalez was the unlikeliest of opposition standard bearers. The 74-year-old was unknown until he was tapped in April as a last-minute stand-in for opposition powerhouse Machado, who was blocked by the Maduro-controlled supreme court from running for any office for 15 years.
Authorities set Sunday's election to coincide with what would have been the 70th birthday of former President Hugo Chavez, the revered leftist firebrand who died of cancer in 2013, leaving his Bolivarian revolution in the hands of Maduro. But Maduro and his United Socialist Party of Venezuela, which controls all branches of government, are more unpopular than ever among many voters who blame his policies for crushingly low wages that spurred hunger, crippled the oil industry and separated families due to migration.
The president's pitch this election was one of economic security, which he tried to sell with stories of entrepreneurship and references to a stable currency exchange and lower inflation rates. The International Monetary Fund forecasts the economy will grow 4 per cent this year — one of the fastest in Latin America — after shrinking 71 per cent from 2012 to 2020.
But most Venezuelans have not seen any improvement in their quality of life. Many earn under USD 200 a month, which means families struggle to afford essential items. Some work second and third jobs. A basket of food staples to feed a family of four for a month costs an estimated USD 385.
The opposition managed to line up behind a single candidate after years of intraparty divisions and election boycotts that torpedoed their ambitions to topple the ruling party.
A former lawmaker, Machado swept the opposition's October primary with over 90 per cent of the vote. After she was blocked from joining the presidential race, she chose a college professor as her substitute on the ballot, but the National Electoral Council also barred her from registering. That's when Gonzalez, a political newcomer, was chosen.
Gonzalez and Machado focused much of their campaigning on Venezuela's vast hinterland, where the kind of economic activity seen in Caracas in recent years never materialized. They promised a government that would create sufficient jobs to attract Venezuelans living abroad to return home and reunite with their families.
Venezuela's security forces have clashed with large crowds of protesters who've taken to the streets to denounce the re-election of President Maduro as fraudulent
Opinion polls ahead of the election suggested a clear victory for the challenger.
Opposition parties had united behind Mr González in an attempt to unseat President Maduro after 11 years in power, amid widespread discontent over the country's economic crisis.
A number of Western and Latin American countries, as well as international bodies including the UN, have called on the Venezuelan authorities to release voting records from individual polling stations.
Argentina is one country which has refused to recognise President Maduro's election victory, and in response Venezuela recalled diplomats from Buenos Aires.
Diplomats from six other Latin American countries - Chile, Costa Rica, Panama, Peru, the Dominican Republic and Uruguay - have also been withdrawn for what Foreign Affairs Minister Yvan Gil described on social media as "interventionist actions and statements".
Venezuela's government also announced a temporary suspension of commercial air flights to and from Venezuela with Panama and the Dominican Republic starting from 20:00 local time on Wednesday.
A heavy military and police presence, including water cannons, was on the streets of Caracas with the aim of trying to disperse protesters and prevent them from approaching the presidential palace.
Crowds of people chanted “Freedom, freedom!” and called for the government to fall.
Footage showed tyres burning on highways and large numbers of people on the streets, with police on motorbikes firing tear gas.
In some areas, posters of President Maduro were ripped down and burned while tyres, cars and rubbish have also been set alight.
Armed police, military and left-wing paramilitaries who are sympathetic to the government clashed with protesters and blocked off many roads around the city centre.
The BBC spoke to a number of people who attended one protest in a densely-populated area known as La Lucha, meaning “the fight”.
Paola Sarzalejo, 41, said the vote was “terrible, fraud. We won with 70%, but they did the same thing to us again. They took the elections from us again.
“We want a better future for our youth, for our country."
Her father Miguel, 64, agreed, saying: “He lost the elections, he has no right to be there right now.”
He added: “We want a better future for the youth because if not they will leave the country. One where they can work well and earn well. We have a rich country and he is destroying everything.
“If the youth all leave, only old people will be left in Venezuela, only senior citizens.”
Paola and Miguel Sarzalejo, and other protesters
The Sarzalejos (C) are concerned that most young people will leave Venezuela because of Mr Maduro
Cristobal Martinez, draped in a Venezuelan flag, said he thought the election was a “fraud”.
He said most young people in La Lucha and surrounding areas had voted in an election that was particularly important for young people as “many of us are unemployed” and “the majority do not study”.
"It was the first time I have voted in my life. I was there from six in the morning until approximately nine in the morning and I saw a lot of people mobilising in the street.
"There was a lot of discontent towards the government. The majority of people were participating for change.”
He said while President Maduro had been in office for a long time there had not been “any change” and it had been “worse since President Chavez died”.
He accused some older people who sympathised with the government of living off bonuses or food handouts whereas “we want a change, we want decent jobs, a good future for our country”.
Mr Martinez said he wanted “people from other countries to help us... so that a disaster doesn’t happen like in previous times”.
Mr Maduro has accused the opposition of calling for a coup by disputing the results. "This is not the first time we are facing what we are facing today,” he said.
“They are trying to impose in Venezuela a coup d'etat again of fascist and counter-revolutionary character."
The Venezuelan attorney general warned that the blocking of roads or breaking any laws related to disturbances as part of protests would be met with the full force of the law and that 32 people had been detained on accusations ranging from destroying electoral materials to sparking acts of violence.
Meanwhile, US senior administration officials said that the announced result “does not track with data that we've received through quick count mechanisms and other sources, which suggests that the result that was announced may be at odds with how people voted”.
That was “the principal source of our concern”, they added.
“That is why we are asking the Venezuelan electoral authorities to release the underlying data that supports the numbers that they have publicly announced.”
However, the US has not yet been drawn on what the result means for their sanctions policy towards Venezuela. Officials have emphasised that while they have doubts about the result, President Maduro did call an election and allow an opposition candidate to be on the ballot paper - even if the opposition leader was banned from running.
The Organization of American States (OAS) announced late on Monday it will hold a meeting on Wednesday of its permanent council over the Venezuelan results.
