Boko Haram demanded the freedom of terrorist prisoners in exchange for the release of the Chibok schoolgirls today as Nigeria's Islamist gunmen published a new video showing 50 of their captives.
The girls, who were kidnapped from a Christian school in the town of Chibok in 2014, are shown swathed in dark Islamic veils, standing against the backdrop of a black tarpaulin.
In the video, one of the girls identifies herself as Maida Yakubu and says in the Hausa language of northern Nigeria: "What I can say is that our parents should take heart. Talk to the Government so that we can be allowed to go home."
Speaking under obvious duress, she adds: "Oh you, my people and our parents, you just have to please come to our rescue. We are suffering here, the aircraft have come to bombard us and killed many of us".
The girl says: "We are really suffering, there is no food to eat, no good water to drink here".
A masked commander then demands the freedom of Boko Haram terrorists. "We don't want to do anything with these girls, our demand remains the same," he says. "We want the Government to release our fighters who have been in detention for ages; otherwise, we will never release these girls."
The commander accuses Nigeria's Government of killing some Chibok captives in air strikes.
The video provides the first visual proof that scores of the girls are still alive since an earlier production dating from May 2014, a month after the mass abduction. Another video, which emerged in April this year, showed only 15 of the girls.
The credibility of the latest video is enhanced by the fact that Maida Yakuba's mother, Esther, is among the bereaved parents who sent open letters to their missing daughters in April.
The girls are believed to have been forcibly converted to Islam; some have been sold or given to commanders as concubines.
Boko Haram raided a Christian school in Chibok on the night of April 14, 2014, abducting 276 girls, of whom about 200 are still believed to be in captivity.
But the Islamist gunmen have suffered a series of defeats since that incident. In 2014, Boko Haram controlled about 51,800 sq km of northern Nigeria. Their domain covered an area almost twice the size of Belgium, with a population of at least 1.7 million people, where the black flag of jihad flew over scores of towns and villages.
Since then, Nigeria's Government has gone on the offensive, breaking Boko Haram's grip on this territory and recapturing almost all of the population centres that were previously under its flag.
This campaign has benefited from military advice, training and intelligence provided by Britain and America, along with the firepower of the armies of neighbouring African states, particularly Chad.
The result is that Boko Haram has returned to being an insurgent movement and terrorist organisation, rather than a group that governs territory.
The gunmen have also split, with one faction of Boko Haram pledging allegiance to Isis (Islamic State). The Chibok schoolgirls are believed to be in the hands of the rival, non-Isis faction, led by Boko Haram's longstanding commander, Abubakar Shekau, who was a regular voice in earlier videos.
The latest message appears designed to place maximum pressure on Muhammadu Buhari, the Nigerian President, to bargain with Boko Haram and exchange terrorist prisoners for the Chibok girls. The video will also be intended to restore the group's profile and provide a reminder that it remains a threat despite recent defeats.