|The attacks left at least 38 people dead and more were killed in the chaotic aftermath [Reuters]
A Nigerian Muslim group formerly known as Boko Haram has claimed responsibility for series of bombings on Christmas Eve in Nigeria that left at least 38 people dead and sparked violent reprisals.
In a statement published on Tuesday on what is thought to be its website, the group claimed responsibility for the bombings in central Jos and two attacks on churches in Maiduguri.
Nigerian police immediately cast doubt on the claim, but if the claims are true, the attacks would mark the first time Boko Haram strikes outside of the country's predominately Muslim north.
Many analysts have instead attributed the Christmas Eve bombings in Jos to the struggle for political and economic power in between Christian and Muslim ethnic groups in the region.
Hundreds of people have been killed in previous clashes between the two groups.
The website statement read: "O nations of the world, be informed that verily the attacks in Suldaniyya [Jos] and Borno on the eve of Christmas was carried out by us, Jama'atu Ahlus-Sunnah Lidda'Awati Wal Jihad, under the leadership of Abu Muhammad, Abubakar bin Muhammad Shekau."
Boko Haram changed its name following a prison break earlier this year, in which more than 700 inmates were freed, to Jama'atu Ahlus-Sunnah Lidda'Awati Wal Jihad, which translates roughly to "People Committed to the Prophet's Teachings for Propagation and Jihad".
The statement said that the attacks were meant "to start avenging the atrocities committed against Muslims in those areas, and the country in general. Therefore we will continue with our attacks on disbelievers and their allies and all those who help them".
Shekau, the name mentioned in the statement, is a suspected Boko Haram leader. Video footage of a man believed to be Shekau speaking in the Hausa language was also posted on the website.
"We are the ones who carried out the attack on ... Jos," he said in the video. "We are the Jama'atu Ahlus-Sunnah Lidda'Awati Wal Jihad that have been maliciously branded Boko Haram ...
"Everybody knows about the gruesome murders of Muslims in different parts of Nigeria ... Jos is a testimony to the gruesome killings of our Muslim brethren and the abductions of our women and children whose whereabouts are still unknown ...
"My message to my Muslim brethren is that they should know that this war is a war between Muslims and infidels. This is a religious war."
The address for the website had been given in a video that emerged earlier this year purportedly from sect members.
But Abdulrahman Akano, police commissioner for Plateau state, where Jos is the capital, cast doubt on the claim.
"Anybody can post anything on the Internet," he said, adding that the bomb blasts were not the usual method used by Boko Haram.
The Christmas Eve bomb blasts in Jos and the reprisals that followed killed at least 80 people, Nigeria's emergency agency said.
On Monday Nigerian police arrested six people in connection with the violence that erupted in the aftermath of the bombings, but not in connection with the blasts themselves.
Police and the army have declined to identify the bombing suspects. They have also not confirmed if the bombings were related to the church attacks. The two areas are about 520km apart.
Boko Haram is thought to have been defeated in 2009 when the military destroyed its mosque and its leader was arrested. He later died in police custody.
Ban Ki-moon, United Nations secretary-general, has condemned the violence in Nigeria "especially at a time when millions of Nigerians are celebrating religious holidays".
Goodluck Jonathan, the Nigerian president, has expressed his sympathy to the victims' families and committed to bring the perpetrators to justice.
"I assure Nigerians that [the] government will go to the root of this," he said of the explosions. "We must unearth what caused it and those behind it must be brought to book."