At least 18 people were killed and at least 60 more injured Friday in a suicide car bombing at the United Nations headquarters in Nigeria's capital, Abuja, according to U.N. officials.
One wing of the building was completely destroyed, while the lower floors were badly damaged in what media reports have described as “total carnage."
The radical Islamist group Boko Haram claimed responsibility for the car bombing in a phone call to the BBC's Hausa language service.
UN chief Ban Ki-moon said the attack was "an assault on those who devote their lives to helping others," the BBC reports.
Al Jazeera said the building is among the most heavily guarded in Nigeria, housing international diplomats and foreign workers.
The network's correspondent said:
What we are being told by eye witnesses on the ground is that the entire of the front facade of the building has been blown up.
The blast went off at 11 a.m. local time in the diplomatic zone, in the city center, in what is suspected to be a suicide attack. The U.N. information center in Lagos confirmed the blast was caused by a bomb.
An Abuja police said an anti-bomb squad had been deployed to the scene.
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There was no immediate claim of responsibility, but suspicion has fallen on the Islamist sect Boko Haram, which has in the past targeted Abuja.
A U.N. source in Abuja told the BBC that the U.N. had received intelligence last month that it could be targeted by Islamist group Boko Haram.
Boko Haram is pushing for the establishment of sharia law in Nigeria, and opposes Western-style education, politics and general society.