Fresh clashes broke out on Wednesday in an area of northern Nigeria already under a round-the-clock curfew after three previous days of attacks and reprisal violence killed at least 101 people.
Residents and police reported new clashes in a number of areas in and around the city of Kaduna on Wednesday night despite the curfew, but details were not clear.
"We had some breakdown of law and order in a few areas in the city and outside, but the situation has been brought under control," police spokesman Aminu Lawan said. "I am not aware of any fatalities or injuries."
Areas affected in Kaduna on Wednesday included the Barnawa, Malali and Hayin Gada districts.
The violence between Sunday and Tuesday in Kaduna and Damaturu had already led to round-the-clock curfews in both areas and raised fears of further reprisal attacks. Pope Benedict XVI on Wednesday pleaded for calm.
Some in the northeastern city of Damaturu have been stranded and unable to access food since Monday when a shootout between suspected Boko Haram members and soldiers led authorities to impose a ban on movements.
The gun battles, which killed at least 40 people, have stopped but the curfew remains in place, said Patrick Egbuniwe, police commissioner of Yobe State, where Damaturu is the capital.
"So far we have four dead policemen, two soldiers and 34 insurgents," said Egbuniwe.
An auto mechanic in the restive city said he has not been home since the fighting started.
"I have been in my workshop since Monday," Gambo Bakanike told AFP. "We have an open well from which we can get our drinking water, but we have run out of food."
A senior hospital official said he and his staff have also been stranded since Monday.
"There is water but we don't have any food. Our families can't bring us anything because of the curfew," said the official who asked to remain anonymous.
West of Yobe in Kaduna state, residents largely remained indoors after three days of religion-fueled violence that killed at least 61 people.
Boko Haram claimed suicide attacks at three churches in the state on Sunday, which killed at least 16 people and sparked reprisal violence by Christian mobs who burned mosques and targeted their neighbours, killing dozens.
Hours after the rioting began, officials imposed a state-wide ban on movements, which was briefly eased on Monday, but reinstated when the other sector started reciprocal rioting.
National police spokesman Frank Mba said he was "confident the curfew would be relaxed soon," insisting that the police have enough men in Kaduna "to manage any eventuality."
Burned vehicles and destroyed shops were visible around Kaduna city on Tuesday, according to an AFP reporter who toured the city with the military.
Pope Benedict XVI on Wednesday condemned those "spilling the blood of innocent people."
"I hope all parts of society will collaborate in not taking the road of reprisals," Benedict said during a weekly general audience.
The Boko Haram insurgency has worsened in recent months, with Sunday attacks on religious places.
The criticism directed at President Goodluck Jonathan over what some call his befuddled response to the worsening Islamist violence has also grown sharper in recent days.
"Since these terrorist acts began, nothing the president, Dr. Goodluck Ebele Jonathan, has done has been reassuring that the end to this spate of bombings and gun attacks is in sight," the Christian Association of Nigeria said.
A major oil workers union in Africa's largest crude producer also issued harsh criticism of the government.
"Governments are put in place to solve problems, not to join the populace in lamenting about them," the Petroleum and Natural Gas Senior Staff Association of Nigeria said in a statement.
It told Jonathan's administration "to wake up to its primary responsibility i.e. the security and welfare of the people."
Boko Haram has killed more than 1,000 people in Africa's most populous country since mid-2009.