A bomb blast that struck a convoy of military vehicles in the heart of Turkish capital Ankara, left at least 28 people dead and 61 others wounded Wednesday, in an escalation of attacks across the country.
The car bomb exploded when a convoy of military buses carrying soldiers stopped at traffic lights in central Ankara.
Smoke rising from the blast scene could be seen from all over the city, close to the headquarters of the Turkish military and the parliament. The blast could also be heard throughout Ankara.
Deputy prime minister Numan Kurtulmus confirmed the toll in the car bomb attack and the government vowed retaliation, but it was still unclear who had carried out the attack.
President Recep Tayyip Erdogan blamed the spate of deadly strikes in Turkey on jihadists and Kurdish rebels. "Turkey will not shy away from using its right to self-defence at any time, any place or any occasion," Erdogan warned.
Both Erdogan and Prime Minister Ahmet Davutoglu scrapped today's planned trip to Brussels to discuss Europe's migrant crisis.
NATO ally Washington issued a statement strongly condemning "the terrorist attack on Turkish military personnel and civilians" and reaffirmed US solidarity with the key partner.
NATO secretary-general Jens Stoltenberg said the alliance strongly condemned the bombing. "NATO Allies stand shoulder to shoulder in the fight against terrorism," he said.
The army said the attack took place at 1631 GMT and had targeted "service vehicles carrying army personnel".
In Ankara, ambulances and fire engines were sent to the scene and wounded victims were seen being taken away on stretchers.
Images showed firefighters trying to overcome a fierce blaze engulfing the gutted service buses.
Turkish police threw a security cordon around the area. A second blast later rocked the area, an AFP correspondent said, but officials said this was police detonating a suspicious package.
The EU pledged to stand "with Turkey and its people in these difficult times".
Kurtulmus said authorities did not know who had carried out the attack, but vowed the perpetrators "will be revealed as soon as possible".
Ankara is already on alert after 103 people were killed on 10 October when two suicide bombers belonging to the Islamic State blew themselves up in a crowd of peace activists, the bloodiest attack in the country's modern history.
An IS suicide bomber also killed 11 German tourists on 16 January, when he blew himself up in the tourist heart of Turkey's biggest city Istanbul.
Turkey also faced two other deadly bombings in the country's Kurdish-dominated southeast earlier in the year.
Turkey is also waging war on several fronts - against the outlawed Kurdistan Workers' Party (PKK), which has repeatedly attacked members of the security forces in the southeast, the banned ultra-left Revolutionary People's Liberation Party–Front (DHKP-C) has also staged a string of usually small-scale attacks in Istanbul over the last few and now the Syrian Kurdish Democratic Union Party (PYD) and its People's Protection Units (YPG) are merely the Syrian branch of the PKK and themselves terror groups.
Turkish artillery in the south of the country shelled positions of Kurdish fighters in Syria for the fifth day in a row on Wednesday in an escalating standoff, reports said.