A car bomb in Turkish capital Ankara killed 28 people on Wednesday and injured more than 60.
A car laden with explosives detonated next to military buses at a traffic light in one of the most daring attacks against the Turkish military.
Several bomb attacks have targeted Turkey ever since it got dragged into the chaotic war in Syria.
The attack, whose victims were mostly military personnel, happened close to the parliament building and the armed forces' headquarters.
Turkey's Deputy Prime Minister Bekir Bozdag said the blast was an "act of terrorism", while the military said attack was "a treacherous terror act".
President Tayyip Erdogan said Turkey will get stronger in its self defense and it was determined to continue the fight against the perpetrators.
"We will continue our fight against the pawns that carry out such attacks, which know no moral or humanitarian bounds, and the forces behind them with more determination every day," he said in a statement.
NATO Secretary-General Jens Stoltenberg condemned the attack saying: "NATO allies stand shoulder to shoulder in the fight against terrorism."
No group has claimed responsibility for the attack, which has heightened security concerns in the capital of a NATO member.
In another incident on Wednesday, an explosion took place at the Turkish cultural centre in the Swedish capital Stockholm.
The explosion damaged the building that housed the centre but no one was injured.
In October last year, serial explosions targeting a peace march had killed more than 100 people.
Again in January, a suspected Isis suicide bombing in Istanbul killed at least 10 people, mostly German tourists.