Nigeria: Boko Haram claims responsibility for blast that killed 75

Nigeria's armed group Boko Haram has become increasingly violent in recent weeks, including a deadly bombing Monday at a busy bus station in the capital Abuja — for which the group claimed responsibility Saturday. That attack occurred just hours before 129 schoolgirls were abducted in the northeastern town of Chibok, a brazen act that authorities suspect was committed by Boko Haram.

The admission to the bus station bombing, which left 75 people dead, came in a video received Saturday. The leader of the Boko Haram network, Abubakar Shekau, threatened more attacks saying, "We are in your city, but you don't know where we are."

At least 44 of the schoolgirls abducted in Chibok have since been released and have reunited with their parents, according to the Borno state education commissioner. 

A town official said people angry at the military's failure to find the abductees are taking the initiative and searching for the girls, ages 15 to 18, in a nearby wooded area, the Sambisa Forest — dangerous because it is a known hiding place for members of Boko Haram and because it has been pounded by near-daily aerial bombardments by the air force.

Boko Haram, which loosely translates as "Western education is forbidden," has as its main aim the establishment of a separate Islamic state in the country's northeast. Nigeria, Africa's most populous nation, has a population of about 170 million, divided almost equally between Muslims mainly in the north and Christians in the south.

In the new video, Shekau, declared a global terrorist by the U.S. with a $7 million bounty on his head, spoke in Arabic and the Hausa language that is dominant in northern Nigeria.

He made no mention of the abductions, but the military, local officials and girls who have escaped have blamed that attack on Boko Haram.

The military had mistakenly announced this week that it had freed nearly all the girls from their captors, before redacting their statement.

Boko Haram's violent campaign poses a severe threat to the cohesion and security of the central Nigerian government ahead of elections in February 2015.

More than 1,500 people have been killed in the fighting this year, compared to an estimated 3,600 between 2010 and 2013.

The attacks have undermined the Nigerian government and military claims that they are containing the unrest in the extreme northeast of the country.

Al Jazeera and The Associated Press