Takfiri Boko Haram militants have killed more than 100 people in a raid on a town in Nigeria’s northeastern Borno State, reports say.

Abbas Gava, the spokesman for a civil defense group, said on Sunday that militants hoisted their black and white flag over the town of Damboa, sending letters to the residents of nearby villages threatening to attack and take their areas, too.

“Nine major villages are on the run,” he said, referring to hundreds of people who are fleeing the area.

Survivors said that militants fired rocket-propelled grenades and threw homemade bombs into homes and then opened fire on the people who were trying to flee the attack.

A human rights activist, who spoke on the condition of anonymity, also said that the militants attacked again after people were trying to bury the dead, noting that the death toll has surpassed 100.

Damboa had been under siege for two weeks since the militants removed soldiers from a new camp on its outskirts. The militants exploded a bridge south of the town to cut off access to the region.

The Defense Ministry said the Nigerian forces had repelled the attack and killed 50 militants.

Boko Haram has increased the number of its attacks this year, particularly in northeastern Nigeria. Human Rights Watch (HRW) said in a report earlier this week that some 2,053 civilians have been killed in 95 attacks in the first half of 2014.

Boko Haram - whose name means “Western education is forbidden” - says its goal is to overthrow the Nigerian government. It has claimed responsibility for a number of deadly gun and bomb attacks in various parts of Nigeria since 2009.