KANO, Nigeria (AFP) - A suicide bomber blew himself up on Sunday inside a church in the restive northeastern Nigerian city of Potiskum, killing five worshippers in the latest in a new series of attacks blamed on Boko Haram, a police officer and witness told AFP.
The attacker entered the Redeemed Christian Church of God in the Jigawa area on the outskirts of Potiskum and detonated his explosives.
Four worshippers died instantly with a fifth succumbing to her injuries shortly afterwards in hospital, a police officer who helped remove the bodies told AFP.
"The victims included a woman and her two children, the pastor and another worshipper," added the officer, who spoke on condition of anonymity.
Witness Garba Manu told AFP that the bomber arrived on a motorised rickshaw, adding that "as soon as he entered a loud explosion ripped through the church which is under construction."
"I saw him walking in and he didn't raise any suspicion," Manu said.
There was no immediate claim of responsibility but Potiskum, the commercial capital of Yobe state, has been hit repeatedly by Boko Haram Islamists during their six-year insurgency, including in suicide attacks.
The insurgents have also launched a series of attacks on mosques, villages and markets in neighbouring Borno state in the past few days, claiming more than 200 lives.
Washington strongly condemned the attacks, a State Department spokesman said, adding that the US "will continue to support Nigeria's efforts to bring those responsible... to justice".
- Attacks on the rise -
Boko Haram are keen to prove they are not a spent force despite a four-nation military offensive running them them out of several towns and villages they had controlled.
The use of improvised explosive devices and suicide bombings has increased since May 29 when Buhari took office vowing to crush the rebellion.
According to an AFP tally, at least 450 people have lost their lives since Buhari's inauguration.
A statement from the president's office on Sunday quoted him as condemning "the resumption of attacks by terrorists on places of worship which are highly revered places of prayer and communion with God for most Nigerians."
"Nigerians are a very religious people and President Buhari believes that the terrorists who wantonly attack our places of worship have wilfully declared war on all that we value, and must therefore be confronted with all our might and collective resolve," it said.
It said the president would do "everything possible to eradicate Boko Haram, terrorism and mindless extremism from Nigeria in the shortest possible time."