Nigeria's Boko Haram Islamists on Monday claimed suicide attacks at three churches that sparked reprisals by Christian mobs who rampaged and burned mosques, with at least 52 people dead.
The church attacks, an almost weekly occurrence in Nigeria in recent months, left at least 16 dead and triggered a wave of fierce revenge attacks that killed more than twice as many.
Officials on Sunday had imposed a state-wide 24 hour curfew in Kaduna state, where the attacks occurred, as rescuers combed deserted streets for bodies and searched for those wounded by rioters who vowed to avenge the church blasts.
The mobs had moved through the streets in the northern city of Kaduna on Sunday with machetes and clubs while also torching at least three mosques, petrol stations and vehicles. A number of the victims' bodies were burnt.
Boko Haram, responsible for more than 1,000 deaths since July 2009, said the attacks at a church in Kaduna city and two churches in the nearby city of Zaria were a response to the "atrocities Christians perpetrated against Muslims."
"Allah has given us victory in the attacks we launched against churches in (the cities of) Kaduna and Zaria which resulted in the deaths of many Christians and security personnel," said the Boko Haram statement.
Police said the blasts killed at least 16 people, sparking young Christians carrying clubs and machetes to wreak havoc around Kaduna city.
"As of the last count we have 52 dead bodies picked up from the affected areas. We have more than 150 injured," said a senior rescue official who asked to not be named as he was not authorised to issue death tolls.
"Most of the victims were those killed in reprisal attacks."
Red Cross spokesman Nwakpa O. Nwakpa told AFP his staff saw almost no movement as they travelled around Kaduna city on Monday, as residents adhered to the curfew.
The ban on movement has since been relaxed, Kaduna state police spokesman Aminu Lawan told AFP.
"People can move between 2:00 pm and 6:00 pm," he said, adding that situation in the city has been stabilised since the latest unrest in an area hit by heavy inter-communal violence in the recent past.
Following presidential elections last year, rioting in Kaduna state left more than 500 people dead, mostly Muslims.
Police termed the latest riots "a momentary breakdown of law and order".
A resident of Kaduna city's Goni Gora area claimed he saw soldiers shoot dead three members of a Christian mob late on Sunday.
"Three youths were trying to pull down a mosque with an axe. Soldiers came by and asked them to stop but they refused and continued," said the man. "All three were shot dead."
Police spokesman Lawan said he had received no reports of fighting between rioters and security forces.
While banks and shops were closed Monday as troops patrolled the vacant streets, the lockdown did not apply to doctors and nurses, who were allowed to work, state government spokesman Saidu Adamu said.
"Many of (the injured) need surgery, but a shortage of blood is stalling treatment," a Red Cross official in Kaduna said.
The first blast struck ECWA Goodnews Church in the Wusasa area of Zaria city early Sunday. The second explosion went off 10 minutes later at the Christ the King Catholic church in Zaria's Sabongari area, a police statement said.
The third blast hit the Shalom Church in Kaduna city moments later.
Among the victims targeted by the Christian mobs that formed after the blasts were Muslim motorcycle taxi drivers parked near churches and those who typically repair the shoes of the area's churchgoers, a Red Cross official said.
As their insurgency has intensified, Boko Haram's stated demands and grievances have varied widely, prompting speculation that the group is composed of disparate cells, including a hardcore Islamist wing.
The extremists have previously said they intended to create an Islamic state across the mainly Muslim north of Nigeria, Africa's most populous nation of 160 million, where the south is majority Christian.
In their latest statement, they denied "a rumour" that their objective is to destroy northern Nigeria and made reference to the Islamic state that once existed there and was "destroyed" by British colonialists.