At least five people have been killed and 15 others wounded in an explosion in the northeastern Nigerian city of Gombe, witnesses say.

Muhammad Garkuwa, a drivers’ union official, said that the bomb went off near a bus station on Thursday. “The explosion was from an explosive left by a woman in her handbag beside a bus waiting to convey passengers to Jos,” he said. Other witnesses also made similar remarks about the incident. Yusuf Darazo, who sells food near the bus station, said, “No-one suspected her. People around assumed she was making calls before the bus filled up.” “She disappeared and the bag exploded soon after, setting the bus on fire. I saw five dead and several injured,” he said.

No group has yet claimed responsibility for the attack, although Takfiri Boko Haram group often carry out similar attacks. The Takfiris have claimed responsibility for a number of deadly shooting attacks and bombings in various parts of Nigeria since the beginning of their deadly campaign in 2009, which has displaced over 1.5 million people.

Takfiri Boko Haram militants have killed over 7,300 civilians in Nigeria and neighboring countries since the beginning of 2014, the UN says.