The government said all signs so far suggested the the outlawed Kurdistan Workers Party (PKK) was behind the bombing in the city of Kayseri, a usually calm industrial hub in the heart of Anatolia.
Interior Minister Suleyman Soylu said a total of 56 people were wounded, half a dozen of them seriously, and that seven people had been detained on suspicion of involvement while five more were on the run.
Television pictures showed the bus reduced to a smouldering wreck by the blast, which came a week after 44 people were killed in a double bombing in Istanbul after a football match. That attack was claimed by Kurdish militants.
“All indications at present point to the PKK,” Deputy Prime Minister and government spokesman Numan Kurtulmus told NTV television.
He said that the materials used in the bombing were similar to those used in the Istanbul attack last week. “You don’t just buy these at the shopping mall ... there is a logistical support,” he said.
Prime Minister Binali Yildirim said that the attack was carried out by a “suicide bomber”, without giving further details.
‘National mobilisation’
The bus — carrying low-ranking privates and non-commissioned officers — was attacked after leaving the commando headquarters in the city to take the off-duty soldiers on a shopping trip.
Those killed were in their early 20s, reports said.
President Recep Tayyip Erdogan said that the “acts of terror” in Turkey were “aiming at all 79 million of our citizens together with our soldiers and police.”
Without referring specifically to the Kayseri attack, he said that Turkey was targeted by all terror groups but especially the PKK. “We will fight decisively against these terror organisations in the spirit of a national mobilisation,” he said.
Turkey has seen a spate of deadly bombings in a bloody 2016 blamed both on jihadists and Kurdish militants that have left dozens dead and put the country on daily alert.
In June, 47 people were killed in a triple suicide bombing and gun attack at Istanbul’s Ataturk airport, with authorities blaming the militant Islamic State group.
HDP offices attacked
One of the main cities of central Turkey, Kayseri is a key industrial hub with a population of over one million and a stronghold of Turkish nationalists.
The city lies close to the famous landscapes of Cappadocia, a magnet for tourists around the world.
It is well west of the south-east of the country that has been hit by months of deadly fighting between the PKK and the security forces.
Following the bombing, dozens of protesters stormed the offices of the pro-Kurdish Peoples’ Democratic Party (HDP) in Kayseri, draping a Turkish nationalist flag from the top floor, footage posted on social media showed.
The HDP condemned the attack on the soldiers “in the strongest possible terms” but said the country has “long passed the stage of settling with messages of condemnation.”
The Turkish military has stepped up operations against the PKK after a fragile ceasefire broke down in the summer of 2015. Since then, there has been a dramatic surge in violence that shows no sign of ending.
Last week’s double bombing in Istanbul, which targeted police after a match of Besiktas football club, was claimed by the Kurdistan Freedom Falcons (TAK) seen as a radical offshoot of the PKK.
