A car bomb exploded in the Turkish capital of Ankara on Sunday, killing 37 people and injuring more than 100, according to the health ministry. Mehmet Muezzinoglu, the health minister, said 71 people were still being treated at the hospital, with 15 in serious condition. Several vehicles were destroyed at the scene in Guven Park in the Kizilay district, a key transport hub. No one claimed responsibility for the attack. President Recep Tayyip Erdogan vowed to defeat terrorists who have attacked Turkey over the past 18 months. "Turkey is fighting a determined struggle against terrorist organizations," he said. The bombing is the second such attack in the city in under a month.