A female suicide bomber blew herself up in a market in Biu, in Nigeria’s north-eastern Borno State on Thursday afternoon, killing herself and seven other people, a security source has said.

“Eight people were killed, including the bomber, who detonated an explosive device near a market in the town of Biu,” the source told The Anadolu Agency, requesting anonymity.

“More than 20 other people were injured, some of whom are in critical condition,” he added.

Salu Maina, a local resident, said the bomber had approached the market in the seconds before the blast occurred.

“It would have been worse if some youths had not tried to intercept her when they saw her making suspicious movements,” Maina told AA by phone, adding that casualties had included members of a local vigilante group.

A trader in the Biu market, Aliyu Buba, told journalists that a 12-seat passenger bus blew up with no warning after driving into the market and parking, around 3:20 p.m. local time.

Witnesses said that a woman or girl on the bus may have set off the blast, according to a Reuters report.

Biu, capital of the Biu local government area, has repeatedly been targeted by militant attacks, which have caused significant human and material damage.

•File photo shows bomb blast in a northern Nigerian market.