Many people were feared killed in a suicide attack at a mosque in Nigeria’s city of Yola, capital of the northeastern state of Adamawa, on Friday, sources here said.

The attack came barely 12 hours after a deadly bomb attack targeted a mosque in the neighbouring Borno State, a security source told Xinhua.

The loud blast was heard when many worshippers were still around the mosque after the weekly congregational prayer, said the security source who pleaded for anonymity.

It was unclear whether the attack was carried out by a male or female suicide bomber, the unnamed source said, adding that security operatives had cordoned off the area and rescue operations were on.

Suicide attacks targeting mosques in northern Nigeria have been frequent since last week. The militant group Boko Haram was blamed for the attacks.

Earlier on Friday, a suicide attack on a mosque in Borno State left at least six people dead and more than 17 injured. The explosion was carried out by a suspected lone suicide bomber whose two accomplices escaped when some vigilant members of the community accosted them after being alerted by their suspicious movements, said a resident identified as Manaseh Adamu.