Thousands of Nigerians living in the northeastern parts of the country have escaped violence by Boko Haram Takfiri militants.

The people fled to neighboring Cameroon on Monday following an attack by the militants on the border town of Gamboru Ngala.

According to reports, Boko Haram launched its assault on a police station and a military base at 05:30 a.m. local time (0430 GMT).

"The sounds (of gunfire) became more deafening as police and soldiers responded to Boko Haram," a witness said.

The latest development came after the militants declared a so-called caliphate in the northeastern town of Gwoza.

In a recently-released 52-minute video, Abubakar Shekau, the leader of the group, said that he has created the “caliphate” in Gwoza after bringing it under control earlier this month.

Shekau added that he and his militants have come to stay in the town and they do not intend to leave.

Nigeria's military, however, dismissed his claims about the seizure of the town.

"That claim is empty," Defense Ministry spokesman Chris Olukolade said.

Shekau had earlier expressed support for the notorious leader of ISIL Takfiri group Abu Bakr al-Baghdadi, who has declared himself "the caliph", in a video released in July.

The ISIL terrorists declared a so-called caliphate in parts of Syria and Iraq in June.

Boko Haram has claimed responsibility for a number of deadly gun and bomb attacks in various parts of Nigeria since the beginning of its militancy in 2009. Over 10,000 people have so far been killed in the assaults.

Boko Haram -- whose name means “Western education is forbidden” -- says its goal is to overthrow the Nigerian government.