At least 18 people were killed in Friday's car bomb attack on the UN building in the Nigerian capital, Abuja, a police spokesman was quoted in Western media reports as saying.
The powerful explosion occurred when a car rammed into the building after crashing through two security barriers, witnesses were quoted by BBC as saying.
The police source said at least eight people were injured in the blast, while the BBC report put the figure at 60.
Those injured have been hospitalized. A local hospital official was quoted by CNN as saying there was a shortage of blood to use in surgery.
Rescue officials have been working at the scene, helping to pull people from the rubble, media reports said.
No one has claimed responsibility for Friday's attack, but government officials have blamed "terrorists" for the bombing, the BBC said.
A wave of militant violence has swept the oil-rich African country since presidential elections in May, won by Christian Goodluck Jonathan. Boko Haram, a group which wants the establishment of Sharia law in Nigeria, has claimed responsibility for a series of attacks carried out in the country in the past few months.
