Islamist sect Boko Haram claimed responsibility for a wave of Christmas Day bombings on Sunday, including an attack on a Catholic church that killed at least 35 people.
Boko Haram spokesman Abu Qaqa claimed the bombings in a statement to the journalists' association of Maiduguri, capital of the group's heartland.
The Christmas Day attacks show the growing national ambition of Boko Haram, which is responsible for at least 491 killings this year alone, according to an Associated Press count. The assaults come a year after a series of Christmas Eve bombings in Jos claimed by the militants left at least 32 dead and 74 wounded.
The first explosion on Sunday struck St. Theresa Catholic Church in Madalla, a town in Niger state close to the capital, Abuja, authorities said.
The first explosion on Sunday struck St. Theresa Catholic Church just after 8 a.m. The attack killed 35 people and wounded another 52, said Slaku Luguard, a coordinator with Nigeria's National Emergency Management Agency.
"We were in the church with my family when we heard the explosion. I just ran out. Now I don't even know where my children or my wife are,'' Timothy Onyekwere told Reuters. "I don't know how many were killed but there were many dead.''
"I want to know if my wife is dead or alive," a man yelled as he tried to enter the area holding dead and wounded.
Nigeria's National Emergency Management Agency already has acknowledged it didn't have enough ambulances immediately on hand to help the wounded. Luguard also said an angry crowd that gathered at the blast site hampered rescue efforts as they refused to allow workers inside.
"We're trying to calm the situation," Luguard said. "There are some angry people around trying to cause problems."
President Goodluck Jonathan, a Christian from the south who is struggling to contain the threat of Islamist militancy, called the incident "unfortunate" but said Boko Haram would "not be (around) for ever. It will end one day."
The White House condemned the violent attacks, which it said appeared to be acts of terrorism.
"We condemn this senseless violence and tragic loss of life on Christmas Day," the White House said in a statement released from Hawaii, where President Barack Obama is vacationing.
"We have been in contact with Nigerian officials about what initially appear to be terrorist acts and pledge to assist them in bringing those responsible to justice," it said.
Jos, Yobe attacks
In Jos, a second explosion struck near a Mountain of Fire and Miracles Church, government spokesman Pam Ayuba said. Ayuba said gunmen later opened fire on police guarding the area, killing one police officer. Two other locally made explosives were found in a nearby building and disarmed, he said.
"The military are here on ground and have taken control over the entire place," Ayuba said.
The city of Jos is located on the dividing line between Nigeria's predominantly Christian south and Muslim north. Thousands have died in communal clashes there over the last decade.
There were also three attacks targeting a church, the police and army in Yobe in the north of the country, BBC News reported. Yobe has been at the center of clashes between militants and Nigeria's security forces, according to the BBC.
The U.S. Embassy in Nigeria's capital of Abuja had issued a warning Friday to citizens to be "particularly vigilant" around churches, large crowds and areas where foreigners congregate.
Residents of the northeastern city of Damaturu also reported two blasts but there were no details immediately available.
Several days of fighting in and around Damaturu between the sect and security forces already had killed at least 61 people, authorities said.
On Sunday, local police commissioner Tanko Lawan said two explosions had struck Damaturu, including a suicide car bombing. Lawan said that blast happened around noon, targeting the headquarters of Nigeria's secret police in the area. There was no immediate information about casualties, he said.
In the last year, Boko Haram has carried out increasingly bloody attacks in its campaign to implement strict Shariah law across Nigeria, a nation of more than 160 million people.
Boko Haram, which is loosely modeled on the Taliban movement in Afghanistan, claimed responsibility for a Nov. 4 attack on Damaturu, Yobe state's capital, that killed more than 100 people. The group also claimed the Aug. 24 suicide car bombing of the U.N. headquarters in Nigeria's capital that killed 24 people and wounded 116 others.
The sect came to national prominence in 2009, when its members rioted and burned police stations near its base of Maiduguri, a dusty northeastern city on the cusp of the Sahara Desert. Nigeria's military violently put down the attack, crushing the sect's mosque into shards as its leader was arrested and died in police custody. About 700 people died during the violence.
While initially targeting enemies via hit-and-run assassinations from the back of motorbikes after the 2009 riot, violence by Boko Haram now has a new sophistication and apparent planning that includes high-profile attacks with greater casualties.
Boko Haram has splintered into three factions, with one wing increasingly willing to kill as it maintains contact with terror groups in North Africa and Somalia, diplomats and security sources say.
Sect members are scattered throughout northern Nigeria and nearby Cameroon, Chad and Niger.