A powerful bomb blew up inside the Nigerian police headquarters in the capital on Thursday, killing a suspected suicide bomber although other casualties were not immediately clear, officials said.
"The police force headquarters has been bombed, everywhere is bombed," deputy national police spokesman Yemi Ajayi told AFP from Abuja.
"A suspected suicide bomber died in the incident. Many vehicles were destroyed," emergency services spokesman Yushau Shuaib said.
The bomb exploded in a car park inside the police headquarters.
Roads leading to the attack site were cordoned off at least a kilometre away as a thick plume of smoke rose from the area.
Another emergency services spokesman said the bomb was in a car in the parking lot.
The explosion is the latest in blasts to have hit the capital since October last year.
The police headquarters is situated less than a kilometre from the presidential offices and residence.
The blast came a day after an Islamist sect behind other deadly attacks, mainly in the country's north, threatened Wednesday "fiercer" action and said it would not enter into talks with the government.
The Boko Haram group, which disclosed for the first time that it had links with Islamists in Somalia, said dialogue with President Goodluck Jonathan has collapsed.
It said it was angered by a police declaration that "the days of Boko Haram are numbered".
"Very soon, we will wage jihad ...," the group said in a handwritten statement.
The sect admitted links with a foreign Islamist group connected to Al-Qaeda, although security experts had already speculated that it had established ties with Islamists in north Africa.
Also known as the Nigerian Taliban, the group launched an uprising in 2009 which was put down by a brutal military assault that left hundreds dead.
The sect, which has pushed for the creation of an Islamic state, has been blamed for shootings of police and community leaders, bomb blasts and raids on churches, police stations and a prison.