Five bombs exploded at churches across Nigeria today, killing dozens.

The radical Islamist group Boko Haram — known for attacking police and security forces, as well as civilians — claimed responsibility for the Christmas Day attacks, Reuters reported.

One explosion ripped through the St. Theresa Catholic Church in Madalla outside the capital during Christmas mass, killing 25 people, the Associated Press reported. Another bomb hit the city of Jos, which has seen unrest between Christians and Muslims.

"We were in the church with my family when we heard the explosion. I just ran out," Timothy Onyekwere told Reuters. "Now I don't even know where my children or my wife are. I don't know how many were killed but there were many dead."

The LA Times reported that:

In all, at least 39 people were killed Sunday during ongoing sectarian violence in Nigeria, which also included at least three explosions in Yobe, an agricultural state in the country’s northeast that has often been at the heart of fighting between security forces and Boko Haram.

More from GlobalPost: Scores dead in Boko Haram clashes

Hours later, there were blasts at the Mountain of Fire and Miracles Church in Jos and at a church Yobe.

Boko Haram, which has been called the "Nigerian Taliban," also claimed an assault on Christians in Nigeria last year that killed at least 32 people.

The bombings renewed fears that the militant group is trying to ignite a civil war between the Muslims and Christians in Nigeria. The group is accused of killing more than 250 people since July 2010.

The Christmas attacks this year come a day after there were reports of militants with Boko Haram clashing with Nigerian troops in the northeast and killing at least 50 people over a few days.