Radical Muslim sect claims bombs on Nigerian churches.

The Associated Press - A radical Muslim sect ramped up its wave of terror in Nigeria on Sunday with two deadly bombing attacks, including one that killed 25 during Christmas Mass at a Catholic church near the capital.

The sect known as Boko Haram, which has killed at least 491 people this year, claimed responsibility for the attack on St. Theresa Catholic Church in Madalla and also for the bombing of the Mountain of Fire and Miracles Church in Jos, where a police officer died during a subsequent gun battle.

A year ago, the sect claimed responsibility for a series of Christmas Eve bombings in Jos that left 32 dead and 74 wounded. The city of Jos is on the dividing line between Nigeria's predominantly Christian south and the Muslim north.

In Madalla on Sunday, rescue workers scrambled through the rubble of the church to save the injured. An angry mob around the bomb site was hampering their efforts.

"We're trying to calm the situation," said Slaku Luguard, a co-ordinator with Nigeria's National Emergency Management Agency. "There are some angry people around trying to cause problems."

A Boko Haram spokesman later phoned a Muslim newspaper to claim responsibility for the attacks.

In the northeastern city of Damaturu, several days of fighting between sect members and security forces has left at least 61 dead, authorities said Sunday. The police said two explosions struck the city Sunday, one near government offices.

Boko Haram has been campaigning for several years for the implementation of shariah law in Nigeria. Its members are scattered throughout northern Nigeria and nearby Cameroon, Chad and Niger.

On Friday, the U.S. Embassy in Nigeria's capital of Abuja issued a warning to American citizens to be "particularly vigilant" around churches and large crowds.