“forty two dead bodies and 70 wounded were taken to the Mirwais Hospital,” a spokesman for the southern city's central hospital said.
The cause of the blasts was not immediately identified, but it came exactly a week after a suicide bomb attack on Shia worshippers in the northern city of Kunduz, that was claimed by the militant Islamic State group.
The explosion caused heavy casualties, Interior Ministry spokesman Qari Saeed Khosti said.Khosti said authorities were collecting details of the explosion.
Interior ministry spokesman Sayed Khosti said on Twitter: “We are saddened to learn that an explosion took place in a mosque of the Shia brotherhood in the first district of Kandahar city in which a number of our compatriots were martyred and wounded.”
Taliban special forces arrived in the area “to determine the nature of the incident and bring the perpetrators to justice”, he added.
Taliban spokesman Bilal Karimi reported the number of dead and wounded. But a local hospital official – who was not authorised to speak to the media and spoke to The Associated Press news agency on condition of anonymity – gave a higher toll, saying at least 37 people were killed and more than 70 wounded.
There was no immediate claim of responsibility for the attack, but Islamic State in Khorasan Province, ISKP (ISIS-K) claimed a similar bombing that killed scores of Shia people at a mosque in the northern city of Kunduz a week earlier.
“We are saddened to learn that an explosion took place in a mosque of the Shia brotherhood in the first district of Kandahar city in which a number of our compatriots were martyred and wounded,” he said in a tweet.
“Special forces of the Islamic Emirate have arrived in the area to determine the nature of the incident and bring the perpetrators to justice.”
Photographs posted by journalists on social media showed many people apparently dead or seriously wounded on the floor of the mosque.
An eyewitness told AFP he heard three explosions, one at the main door of the mosque, another at a southern area, and a third where worshippers wash themselves.
Another witness said three blasts rocked the mosque in the centre of the town during Friday prayers.
Nematullah Wafa, a former member of the provincial council, said the blast occurred at the Imam Bargah and caused heavy casualties but there was no immediate confirmation of the number of dead and wounded.