The video sent to government negotiators by the captors showed the girls wearing black hijabs in an unspecified location, stating their names, that they were taken from Chibok and the date of the recording.

The video, the first concrete indication that at least some of the girls were still alive since a previous video released publicly by Boko Haram in May 2014, was coming two years after the girls were kidnapped.

They were identified by two mothers of the 219 schoolgirls still missing.  Another mother shown the video broke into tears because her daughter was not among the fifteen girls in the video.

All three, however, identified all the girls, as did a classmate, who was at home on the day of the kidnapping.

In the video, each of the fifteen girls calmly stated her name and that she was kidnapped from Chibok Government Secondary School.

At the end of the clip, a girl identified as Naomi Zakaria, made an apparently scripted appeal to whoever is watching, urging the Nigerian authorities to help reunite the girls with their families.

Two parents identified their daughters in the video. PHOTO: CNN

“I am speaking on 25 December 2015, on behalf of the all the Chibok girls and we are all well,” Naomi said. Though it is unclear if the video was recorded on the stated date, but the date embedded in the video matched the date stated by Naomi, a CNN report said.

Though it was unclear if the video was recorded on the stated date, but the date embedded in the video matched the date stated by Naomi, a CNN report said.

However, Minister of Information and Culture, Lai Mohammed, told CNN the girls in the video appeared “under no stress whatsoever” and there had been “little transformation in their physical appearance”.

But he declined to comment directly on the state of talks with Boko Haram, which has previously said it would release the girls only in exchange for captured fighters in Nigerian prisons.

“There are ongoing talks. We cannot ignore leads but of course many of these investigations cannot be disclosed openly because it could also endanger the negotiations,” the minister added.

AFP, quoting an anonymous source, reported that members of Boko Haram made contact with the government in mid-January this year, requesting talks about a possible prisoner swap.

The militants then sent five still photographs of some of the girls, also wearing black hijabs, who were identified by some parents as being among those kidnapped from Chibok.

The government then requested more concrete proof in the form of a video, which was then sent.

Parents of the 219 girls were on Thursday set to hold a prayer vigil at the Government Girls Secondary School in Chibok to mark the second anniversary of the kidnapping.

Boko Haram seized 276 from their dormitories but 57 managed to escape in the hours that followed.