More than 200 schoolgirls being held by Boko Haram militants in Nigeria could be released by Tuesday, a senior presidential source has said.

The head of Nigeria’s military, Air Chief Marshal Alex Badeh, said on Friday that authorities had agreed a ceasefire with the Islamist militant group that would also allow for the girls’ release.

About 300 students were kidnapped in April while sitting exams in a secondary school in the remote north-eastern town of Chibok, 219 of whom remain in captivity.

The unnamed source said on Saturday that the federal government was striving to meet its obligations under the ceasefire so that the students could be released “either on Monday or, latest, Tuesday next week”.

The government spokesman Mike Omeri said only that authorities were “inching closer to the release of the Chibok girls”. Military officials were unavailable for comment.

Boko Haram, which conveys messages in videos by its supposed leader, Abubakar Shekau, has yet to comment on the ceasefire.

The Nigerian military has twice claimed to have rescued some or all of the girls in the months since they were captured, only to back-track hours later.

Negotiations with Boko Haram in recent years have failed to achieve a peace deal, partly because it has several rival factions.

Relatives of the schoolgirls were cautiously optimistic about the ceasefire.

The community leader Pogu Bitrus said “people rejoiced, but with caution” given the previous false claims made by the government and military.

Bana Lawan, the chairman of Chibok local government area, said: “We don’t know how true it is until we prove it. We will know the negotiations were successful when we see the girls physically. And then we will know it is true. And then we will celebrate.”

The kidnappings sparked global outrage and a social media campaign under the hashtag #bringbackourgirls that was backed by figures including the US first lady, Michelle Obama.

Campaigners have staged daily rallies in the capital, Abuja, to maintain pressure on the government and President Goodluck Jonathan, who has faced mounting criticism for the failure to secure the girls’ release. Jonathan is expected to declare that he is standing for re-election, and positive news about the hostages and insurgency could deflect criticism of his handling of the crisis.

Boko Haram has killed thousands of people in its attempt to establish an Islamic state in religiously mixed Nigeria. Just over half of the country’s 167 million people are Muslim, with most of the rest identifying as Christians.

•Text courtesy of The Guardian of London. Photo shows some of the abducted Chibok schoolgirls as appeared in a Boko haram video.

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