More than 24 hours after Nigerian officials claimed to have reached a deal with Boko Haram militants to free more than 200 schoolgirls, relatives of the teenagers were still anxiously waiting for news about their return.

Senior government and military officials on Friday said they had struck a ceasefire agreement with the Islamists ravaging the country's north.

The deal reportedly included the release of the 219 girls whom the extremists seized from their school in April in a case that drew global outrage and sparked a #BringBackOurGirls campaign that included the likes of First Lady Michelle Obama and Pakistani Nobel Peace laureate Malala Yousafzai.

But there was still no confirmation from Boko Haram's leader and some senior Nigerian officials have questioned the claim.

Reports on Saturday of attacks by gunmen believed to be Boko Haram Islamists in Abadam, a town near the border with Niger, further threw the purported truce into doubt.

The claims could not be independently verified.

A precedent of previous government and military claims about an end to the deadly five-year conflict and the fate of the missing teenagers have also left the relatives cautious.

"We hope it is not deception because we have some doubt," Enoch Mark told AFP from Chibok, the town where the girls, including his daughter and two nieces, were kidnapped.

"This is what we have been itching to hear for the past six months," said Ayuba Chibok, whose niece is among those seized. "My prayer is that the two sides will honor the agreement."

Friday's announcement was made by Chief of Defence Staff Air Marshal Alex Badehand and Hassan Tukur, a senior aide to President Goodluck Jonathan.

But the Nigerian government's own security spokesman, Mike Omeri, said that no deal had yet been reached on releasing the girls.

And Ralph Bello-Fadile, an advisor to Nigeria's National Security Advisor, cautioned that the NSA has been inundated with fraudsters claiming to represent Boko Haram leader Abubakar Shekau.

The United States said it could not confirm whether a deal had taken place.

Jonathan is expected to declare his bid for re-election in the coming weeks, and positive news about the hostages and the violence would likely give him a political boost.

Jonathan's aide Tukur said he represented the government at two meetings with the Islamists in Chad, which were mediated by the country's President Idriss Deby.

"Boko Haram issued the ceasefire as a result of the discussions we have been having with them," said Tukur.

"They have agreed to release the Chibok girls," he said.

Leaders of the #BringBackOurGirls campaign, which has been pressuring the government to act, gave a cautious welcome to a possible release.

"We are really cautious because there have been many times that such optimism has been expressed but did not materialize," Obi Ezekwesili, a former education minister said in a television interview on Saturday.

"But all the same, we are hopeful," she said.

Ndjamena refused to comment but security sources in the country said Chad, which Jonathan visited for talks with Deby early last month, had been involved in the discussions.

The source also said a ceasefire agreement was reached as well as the release of 27 hostages, 10 of them Chinese nationals, who were kidnapped in northern Cameroon earlier this year.

The release of the hostages last weekend was "a first strong signal" from Boko Haram to prove their good faith, the source added but did not mention the schoolgirls.

Cameroon announced on Friday that eight of its soldiers and 107 Boko Haram fighters were killed during fierce fighting in its far north region on Wednesday and Thursday.

A police officer told AFP that at least 30 civilians had been killed by Boko Haram before the military ambush.