Gunmen kill 6 in attack on church in Nigeria. Via CNN

Via CNN -- Gunmen in northern Nigeria attacked a church's Christmas Eve services, killing six people and setting the building on fire, police said.

A pastor was slain in the incident, police said.

It was the latest strike against Christians in the region. More than 30 people died in a wave of Christmas Day attacks in the north last year, blamed on Boko Haram, a militant group that has targeted Christians and Muslims it considered insufficiently Islamist.

"Suspected members of the group have bombed or opened fire on worshipers in at least 18 churches across eight northern and central states since 2010. In Maiduguri, the group also forced Christian men to convert to Islam on penalty of death," Human Rights Watch said in an October report.

It is not immediately known if the group was behind the latest attack.

The Christmas attack came as families whose kin died in last year's killings delivered graveside prayers for a peaceful holiday period. Nigerian President Goodluck Jonathan issued a statement promising better days next year, including better security.

"Sometimes, challenges make people doubt the sincerity of government, but I am confident that God knows everything," he said Sunday.

But residents told CNN that despite assurances of security, they have been attacked again.