A bomb attack struck a bustling pedestrian thoroughfare in central Istanbul on Sunday, killing at least six people in what officials said could be a terrorist attack and shattering a sense of calm as Turkey’s tourist industry works to recover from the pandemic.

The attack was the deadliest in Turkey in more than five years, and authorities offered few details in the hours afterward other than to say they were investigating the possibility that the bomb had been detonated by a woman. President Recep Tayyip Erdogan vowed to punish those behind the blast, without accusing any specific group.

"Efforts to make Turkey and the Turkish nation surrender by terror will not reach their aim today, as they did not in the past,” Erdogan told reporters before flying to Indonesia for the Group of 20 summit.