ABUJA (Reuters) - An Islamist sect claimed responsibility on Friday for an explosion at Nigeria's police headquarters that officials fear may have been the first suicide bombing in Africa's most populous country.
Police said they believed a suicide bomber detonated the explosives that tore through a car park outside their headquarters in the capital Abuja on Thursday, killing several people. They blamed the Islamist sect Boko Haram.
The Daily Trust, a newspaper with a large readership in the mostly Muslim north, on Friday published what it said was a statement signed by Abu Zaid, a spokesman for the group.
"We would speak on the details of the Mujahid (bomber) at the appropriate time but the fact is that he is a martyr who sacrificed his life for the sake of Allah," the statement said.
It did not make clear if the bomber had killed himself intentionally. Security analysts say only forensic tests may show whether he meant to blow himself up or the explosives detonated accidentally while he was still in the vehicle.
Boko Haram has an ill-defined structure and chain of command and it was not possible to verify the statement independently.
The explosion occurred less than three weeks after President Goodluck Jonathan was sworn in for his first full term in office and it followed three coordinated bombings, one inside a military barracks, in the hours following his inauguration.
The violence has catapulted national security in the country, roughly equally split between Christians and Muslims, to the top of his agenda before he has formed a new government.
"Let me use this opportunity to assure Nigerians that it happens all over the world, no country is free," Jonathan told reporters after visiting the site of the explosion.
"Nigeria is also having some ugly incidents lately but surely we will get over it and people should not panic at all, soon most of these things will be a thing of the past," he said.
At least two people were confirmed killed in the blast: the driver of the vehicle which exploded and a police officer who got into the car at a security checkpoint.
Five more body bags were taken from the scene containing body parts and the Red Cross said it was too soon to give a toll.
Attacks by Boko Haram, which wants a wider application of strict sharia Islamic law, had largely been confined to the area around the northeastern city of Maiduguri until recently.
Its views are not widely held by the country's Muslim population, the largest in sub-Saharan Africa.
Its former leader, self-proclaimed Islamic scholar Mohammed Yusuf, was shot dead in police custody during a 2009 uprising in which hundreds were killed. His mosque was destroyed with tanks in what the security forces claimed as a decisive victory.
But low-level guerrilla attacks on police stations and targeted killings of traditional leaders and moderate Islamic clerics, among others, intensified in the second half of 2010.
The group claimed responsibility for Christmas Eve bombings in the central city of Jos and for the bomb attacks which killed at least 16 people when Jonathan was inaugurated on May 29.
The vehicle that exploded on Thursday appeared to have tailed the convoy of Police Inspector-General Hafiz Ringim, who had entered the building moments before the blast, suggesting it may have been an assassination attempt, officials said.
Ringim provoked an angry response from Boko Haram members last week when he said their days were "numbered". A letter, claiming to be from Boko Haram, was delivered to a newspaper in Maiduguri the next day warning of more attacks.
"Very soon we shall embark on jihad on the enemies of God and his prophet," said the letter, written in Hausa, the main language in northern Nigeria.
It said some Boko Haram fighters had returned from training in Somalia, where al Qaeda-linked al-Shabaab rebels control swathes of the country and are fighting the Western-backed government.
Intelligence sources say there is evidence that some members of Boko Haram trained over the border in Niger where al Qaeda in the Islamic Maghreb (AQIM) is known to have a presence, but no evidence of links to Somali militants has ever been made public.