A timeline of abducted Chibok schoolgirls

The abduction of 111 schoolgirls by jihadist militants in Nigeria last week comes four years after the same group kidnapped 276 girls from Chibok, a case that shocked the world.

Here is a recap of the case of the Chibok girls, 112 of whom are still believed to be held.

Snatched from school

On April 14, 2014 Boko Haram gunmen seize 276 girls aged 12 to 17 from the Government Girls Secondary School in the remote town of Chibok in Borno state.

The girls are forced from their dormitories onto trucks and driven into the bush. Fifty-seven manage to flee.

Boko Haram factional leader Abubakar Shekau claims responsibility in a video released on May 5 and vows to sell the girls as slave brides.

A week later a second video shows about 100 of the missing girls. Boko Haram says they have converted to Islam and will not be released unless militant fighters held in custody are freed.

An international media campaign demanding the release of the girls is launched, backed by A-list celebrities and politicians, and the hashtag #BringBackOurGirls goes viral.

One year on

On April 14, 2015 Nigeria's president-elect Muhammadu Buhari warns he "cannot promise" that the girls will be found, as vigils are held to mark their first year in captivity.

In September 2015 Buhari raises the possibility of an exchange of Boko Haram prisoners for the girls.

In December he says he is willing to negotiate with any "credible" Boko Haram leadership if there is proof the girls are alive.

'Proof of life'

In April 2016, on the eve of the abduction's second anniversary, it emerges that Boko Haram has sent a "proof of life" video to the government.

It shows 15 of the girls in black hijabs in the first concrete indication that at least some are still alive.

In May 2016 the Nigerian army confirms the first of the schoolgirls has been found. Aged 19, she has a four-month-old baby and is found with a man she describes as her husband near Boko Haram's Sambisa Forest enclave.

First releases

In October 2016 Nigerian officials announce the release of 21 of the girls following talks between the government and Boko Haram, brokered by Switzerland and the International Committee of the Red Cross.

Local sources say four jihadist prisoners were freed as part of the deal.

The army finds two other girls in November 2016 and January 2017.

In May 2017 another 82 girls are released in exchange for five Boko Haram commanders as part of the same talks.

Later that month, Boko Haram release a video in which a woman claiming to be one of the Chibok girls is seen wearing a black veil and holding a gun.

She proclaims loyalty to Boko Haram and says she does not want to return to her parents.

Early January 2018 the Nigerian army says it has rescued another of the girls in Borno. In all, 107 of the 219 held since 2014 have either escaped or been released.

The militants release a new video purporting to show at least 14 of the Chibok schoolgirls, some carrying babies, saying they were comfortable and wanted to stay with the group.

In mid-February a man involved in the kidnapping is jailed for 15 years in the first conviction in relation to the Chibok case.