Two people, including a bomber, have died in an explosion at Nigeria’s police headquarters in the capital, Abuja, the police say.
Police spokesman Olusola Amore said Islamist group Boko Haram was suspected of being behind the attack.
The blast in the car park of the police base destroyed many vehicles and a large plume of smoke could be seen rising from the scene.
A Red Cross spokesman told the BBC that another four bodies had been recovered.
“Six to be precise. Six bodies from the explosion,” Nigerian Red Cross official Taiye Olaniyi told the BBC’s Focus on Africa programme, adding that many of them had been “very badly mutilated”.
Seven other people were wounded in the explosion, five of whom were being treated in hospital, the Red Cross said.
The BBC’s Jonah Fisher in Lagos says that, for the Nigerian authorities, the attack is an embarrassing strike at the very heart of their security establishment.