* Boko Haram may be split over whether to make peace
* Violence by suspected Islamists has continued unabated
A purported commander of Nigerian Islamist sect Boko Haram declared a unilateral ceasefire on Monday, raising fresh questions about possible rifts within the secretive militant movement as it was not clear if he was speaking for the group.
Sheik Abu Mohammed Ibn Abdulazeez, a man local security sources say is a sect member, twice made statements last year saying Boko Haram is ready for peace talks with the government.
But the group, whose attacks have left hundreds dead since it launched an uprising to try to carve an Islamic state out of Nigeria in 2009, has continued its insurgency unabated. The latest statement is likely to be greeted with scepticism.
In the remarks in English sent to journalists in the northeastern city of Maiduguri, Boko Haram's headquarters, Abdulazeez said Boko Haram had declared "a ceasefire throughout the country with immediate effect ... following a series of meetings with government officials."
It added that he had "the consent and approval of our leader Abubakar Shekau and I call on all members to stop hostilities."
It is unclear if Abdulazeez really is speaking on behalf of Shekau - who has not come out to confirm or denounce him - or whether he represents a rival faction of the Islamist movement seen as the main security threat to Africa's top oil exporter.
The statement came through the usual channels Boko Haram have used to deliver messages; through the Borno state journalists union. It was signed by Abdulazeez who also called to confirm it, union members said.
Shekau denied claims by the government that behind-the-scenes peace talks were being held in October last year, but he has remained silent since Abdulazeez made contact with press in November.
The timing of the alleged ceasefire is likely to be seen as odd given Nigeria's involvement in military efforts to dislodge Islamists in neighbouring Mali, with whom Boko Haram are known to have links. Nigeria's participation in Mali was expected to provoke a violent backlash from Boko Haram.
"We have adopted this measure as a result of the hardship women and children are subjected to, and I urge all members to abide by this directive," Abdulazeez's statement said.
"I urge law enforcement agencies to reciprocate this good gesture," it added.
There was no immediate comment from Nigerian security forces.
Northern Nigeria's conflict has killed around 3,000 people since late 2009, according to Human Rights Watch.
Even if Abdulazeez does not represent Shekau, his statement could add to evidence that military pressure has fragmented Boko Haram, which is now believed to consist of various splinter groups more or less extreme than Shekau's main faction, including ones who have trained with al Qaeda's Saharan wing.
Gunmen killed 23 people in northern Nigeria in attacks that appeared to target gamblers and people selling 'forbidden' meat that Islamist militants disapprove of.
On Sunday, gunmen killed eight in Borno state, an attack that could have been carried out by Islamists or criminal gangs taking advantage of growing lawlessness.
Abdulazeez's statement said any attacks from now on would be the work of "armed robbers and other criminals".