The car bomb blast at a bus stop near Ankara’s central Kizilay square was the second this year, after a military convoy was bombed in the capital in February.
"The Secretary-General sends his heartfelt condolences to the families of the victims. The United Nations continues to support and stand in solidarity with the people and the Government of Turkey at this trying time," the UN statement concluded.
Turkish authorities are yet to say what militant group was behind the recent Ankara bombing, but the February attack was blamed on Kurdish militias.
Earlier in the day, British, French and Russian senior officials and the NATO chief all condemned the deadly bombing in Ankara that claimed 34 lives and wounded 125 people.
In a statement late Sunday, French Foreign Minister Jean Marc Ayrault described the bombing as a "barbaric terrorist attack," adding the recent incident reminded the international community that it must show solidarity, unity and determination in the face of terrorism.