Nigeria's government said Islamic extremists from Boko Haram have agreed to an immediate ceasefire.
But many people expressed doubts about a development that could end an insurgency which has killed thousands and left hundreds of thousands homeless in Africa’s most populous nation.
The fate of more than 200 missing schoolgirls abducted by the insurgents six months ago is still being negotiated, defence ministry spokesman Major General Chris Olukolade said.
But French president Francois Hollande welcomed the "good news" and told a news conference in Paris the girls' release "could happen in the coming hours and days".
France has been involved in negotiations that led to the release of several of its citizens kidnapped by Boko Haram in Cameroon.
The chief of defence staff, Air Marshal Alex Badeh, announced the truce yesterday and ordered his troops to immediately comply with the agreement.
Boko Haram negotiators "assured that the schoolgirls and all other people in their captivity are all alive and well," Mike Omeri, the government spokesman on the insurgency, said. "Already, the terrorists have announced a cease-fire in furtherance of their desire for peace. In this regard, the government of Nigeria has, in similar vein, declared a cease-fire," he said.
But there was no immediate word from Boko Haram, which limits its public engagement to video announcements by its leader, Abubakar Shekau.
Last year, when a government minister charged with negotiations announced an agreement, the group quickly published a video with Shekau denying it. He said then that whoever the government negotiated with did not speak for him, and he would never talk to infidels.
The US, which had sent a team including hostage negotiators to help free the girls, said it could not confirm a ceasefire.
Boko Haram - the group’s nickname means “education is sinful” - drew international condemnation with the April kidnapping of 276 girls and young women at a boarding school in the remote northeeastern town of Chibok.
Dozens escaped in the first couple of days, but 219 remain missing. It could take days for word of a ceasefire to get to fighters of Boko Haram, which is broken into several groups. They include foreigners from neighbouring countries Chad, Cameroon and Niger, where the insurgents also have camps.
Doubts were expressed on Twitter by Ahmad Salkida, a Saudi-based Nigerian journalist living in self-exile because of his links with leaders of Boko Haram. He suggested the ceasefire announcement was a political ploy as President Goodluck Jonathan prepares to announce he will run again for the presidency in February elections.
Mr Salkida said Boko Haram leaders are “miffed” that people are being “easily encased in deceit”.
The chief government negotiator, Ambassador Hassan Tukur, said the Boko Haram representatives he had talked with had provided bona fides by freeing hostages. In an interview with the BBC, he said Boko Haram had promised to release Chinese construction workers kidnapped in Cameroon and the wife of a vice prime minister of Cameroon.
Cameroon announced last Saturday that 27 hostages, including 10 Chinese and the Cameroonian official’s wife, had been released.
Boko Haram had been demanding the release of detained extremists in exchange for the girls. Mr Jonathan originally said he could not countenance a prisoner swap.
The original #BringBackOurGirls protest movement in Abuja, Nigeria’s capital, called for confirmation of the truce from the president.
The principal of the school from which the girls were abducted, Asabe Kwambura, had mixed feelings about the news. “If what we hear is true, I will the happiest person in the world to see these girls of mine return home in one piece,” she said.
But she said many people doubted the government, and the girls should long have been rescued.
Dozens more schoolgirls and boys, young women and men have been kidnapped by the extremists in a five-year-old insurgency. Mr Jonathan told the United Nations last month the extremists have killed 13,000 civilians. Hundreds of thousands have been driven from their homes, many of them farmers, causing a food emergency in the north-east of the country where the insurgency is centred.
In August, Boko Haram began seizing and holding territory where it declared a caliphate, apparently copying the Islamic State group fighting in Iraq and Syria. But the tide appears to have turned in recent weeks, with the military wresting some towns from the extremists and reporting to have killed hundreds of Boko Haram fighters.