Breaking news from The Associated Press:
"A large explosion struck the United Nations' main office in Nigeria's capital Friday, flattening one wing of the building in Abuja. A U.N. official in Geneva called it a bomb attack.
" 'I saw scattered bodies,' said Michael Ofilaje, a UNICEF worker at the building. 'Many people are dead.' He said it felt like 'the blast came from the basement and shook the building.' "
According to the BBC, correspondent Bashir Sa'ad Abdullahi, "who at the site of the explosion, says the ground floor of the building has been badly damaged."
It adds that "emergency services are removing bodies from the building while a number of wounded are being rushed to hospital, our correspondent says."
The Telegraph writes that "dozens are feared dead."
The building is in the same neighborhood as the U.S. embassy.
The BBC adds that there's been no claim of responsibilty (and it is still not certain that it was a bombing), but also notes that "Islamist militants have carried out recent attacks on the city."
We'll update this post as the story develops.