LAGOS, Nigeria — Islamic extremists Saturday claimed responsibility for the massive rush-hour explosion earlier this week that ripped through a busy bus station in Nigeria’s capital, Abuja, killing at least 75 people and wounding 141.

“We are in your city, but you don’t know where we are,” Abubakar Shekau, leader of the Boko Haram terrorist network, said in a new video that threatens more attacks.

“Yes, we are the ones who carried out the attack in Abuja,” he said in Nigeria’s Hausa language in the video.

Shekau made no mention of the abductions of more than 100 girls and young women from a remote northeastern school hours after the bomb blast, also blamed on his fighters.

Officials say dozens of the girls have managed to escape, but 85 remain unaccounted for.

Parents and townspeople have joined security forces and vigilantes searching the Sambisa Forest for the kidnapped girls — an area dangerous because it is known to contain hideouts of the militants.

Monday’s explosion in Abuja, just a 15 minutes’ drive from the presidential villa, was the first attack in two years on the capital, which is in the heart of the country and hundreds of miles from the militants’ traditional stronghold in the northeast.

It undermined government and military claims that they have contained the Islamic uprising to the extreme northeast of the country, and raised fears that the insurgency is spreading.

President Goodluck Jonathan declared a state of emergency in May 2013 and flooded the area with troops who speedily drove the extremists out of towns and villages. But they have been struggling for months now to dislodge the extremists from hideouts in the forest and in mountain caves along the border with Cameroon.

Boko Haram — the nickname means “Western education is sinful” — says Western education and influence have corrupted Africans and only Islamic law can save Nigeria from endemic corruption that is impoverishing citizens of Africa’s biggest oil producer and its economic powerhouse. Nowhere is poorer than the northeast, the birthplace of Boko Haram where only about 5 percent of children finish high school, and only a tiny percentage of those are female.

Copyright 2014 The Associated Press.