Update (12:42 p.m.): CBC News reports that the Islamic group Boko Haram has claimed responsibility for the attack on the UN building in Nigeria. 

Update: Police Commissioner Mike Zuokumor now says at least 18 people were killed and more than 60 injured in today's attack.

A car bomb explosion has killed at least seven people at UN offices in the Nigerian capital of Abuja, reports Sky News. According to witnesses, a vehicle entered the compound's gates and exploded near the four story building. The AP reports that an entire wing of the building has been flattened, leaving "several" dead. "I saw scattered bodies," Michael Ofilaje, a UNICEF worker, tells the news agency. He added that it felt like "the blast came from the basement and shook the building." The offices hold 400 employees and is near the U.S. embassy. Though no one immediately took responsibility for the blast, a banner on the BBC's site notes that the "UN had stepped up security in Nigeria because of warnings that it could be targeted by militant group Boko Haram."  In June, a car bombing that killed two people at police headquarters was blamed on Boko Haram, which advocates the implementation of Shariah law in Nigeria. The Telegraph's foreign staff notes that "dozens are feared dead.

Update: The AP has just uploaded raw video from the attack: