Officials investigating a bomb attack in Ankara that killed six people and injured more than 90 identified a 28-year-old man with a criminal record on Wednesday as the suicide bomber and warned that more attacks could occur.

The attack, the worst in Ankara for at least a decade, is certain to exacerbate political and institutional tensions in Turkey, which are already very high ahead of a July 22 general election. It also raises, once again, the question of how Turkey should respond to the threat of terrorism, a debate that could have a significant impact on the election campaign.