By Camillus Eboh and Joe Brock
ABUJA (Reuters) - A suspected suicide bomber detonated explosives outside Nigeria's police headquarters on Thursday, officials said, killing several people and marking a serious deterioration in security in the West African nation.
There was no immediate claim of responsibility but police said they suspected radical Islamist sect Boko Haram, which has been behind almost daily attacks in the remote northeast and claimed a series of bomb blasts further afield last month.
Dozens of vehicles were set ablaze by the blast, which struck the car park outside the building. Thick black smoke billowed into the sky. Red Cross workers loaded body bags into ambulances but said it was too early to give a death toll.
"We have two whole bodies, one burned beyond recognition. Then we have parts of bodies and it is not possible to determine how many are dead," said Red Cross official Umar Mairiga.
Police spokesman Olusola Amore said the vehicle carrying the suspected bomber was stopped outside the building and directed to the car park to be searched.
"The traffic warden who entered the vehicle of the suicide bomber to direct him to the car park was blown up along with him," Amore said. The National Emergency Management Agency (NEMA) also said a suicide bomber was suspected.
If confirmed, it would be the first suicide bombing in Africa's most populous nation. The blast at what should be one of Nigeria's most secure buildings raised questions about national security less than three weeks after President Goodluck Jonathan was sworn in for his first full term in office.
Witnesses said Police Inspector-General Hafiz Ringim had entered the building shortly before the blast. Ringim was quoted this week as saying Boko Haram's days were "numbered."
"Suicide bombers, if confirmed, are a significant escalation. I guess this was payback for Ringim's imprudent boast," said one Western diplomat on condition of anonymity.
Hours after the Abuja explosion, four children were killed by an apparent bomb near a church in the town of Damboa, around 90 km (56 miles) south of the northeastern city of Maiduguri.
Boko Haram, which says it wants a wider application of strict sharia (Islamic law) across Nigeria, has carried out almost daily attacks in and around Maiduguri in recent months.
Boko Haram's targets have been soldiers, policemen, prison warders and politicians as well as religious and traditional rulers opposed to its ideology. The sect has warned it would carry out more strikes if its demands were not met.
It claimed responsibility for coordinated bomb blasts at popular drinking spots in the towns of Bauchi, Zaria and Zuba that killed at least 16 people hours after Jonathan was inaugurated on May 29.
Jonathan, a Christian from the south of Nigeria, won elections in April which, while deemed Nigeria's most credible for decades, were marred by violence and triggered resentment in some parts of the mostly Muslim north.
Rights groups say as many as 800 people were killed in rioting in the north after Jonathan was announced the winner.
The government dealt with a previous uprising by Boko Haram in Maiduguri in 2009 by sending in the military, leading to days of gun battles in which hundreds of people were killed.
Jonathan could stoke further resentment if he were to do the same again, particularly as critics may draw comparisons with militants in his own southern Niger Delta home region who were given amnesty by the government also in 2009.
Jonathan has named some members of his new administration, including retaining his former national security adviser, but the country is still without a cabinet.
"This attack further highlights the need for an able and effective government team to be formed quickly," said Kayode Akindele, partner at Lagos-based advisory firm JMH-TIA Capital.
"Nigerians are seeking answers from their new president."
(Additional reporting by Afolabi Sotunde in Abuja, Nick Tattersall and Tume Ahemba in Lagos, Ibrahim Mshelizza in Maiduguri; Writing by Joe Brock and Nick Tattersall; Editing by Peter Graff)