Islamist militants of the Boko Haram group have released at least 80 schoolgirls from a group of 276 they abducted in north-eastern Nigeria three years ago, officials say.

The release reportedly came after talks with the government, though few details are confirmed.

The abduction of the so-called “Chibok girls” triggered a global outcry and sparked a huge social media campaign.

Before the latest release, about 195 of the girls were still missing.

Sources told the BBC that the young women were now in the custody of the Nigerian army.

They were brought by road convoy from a remote area to an army base in Banki near the Cameroon border.

After the abduction in 2014, more than 50 girls quickly escaped and Boko Haram then freed another 21 last October, after negotiations with the Red Cross.

The BBC’s Stephanie Hegarty in Lagos says that many families in Chibok will be rejoicing at this latest news, but more than 100 of the girls taken have yet to be returned.

Last month, President Muhammadu Buhari said the government remained “in constant touch through negotiations, through local intelligence to secure the release of the remaining girls and other abducted persons unharmed”.

Many of the Chibok girls were Christian, but were encouraged to convert to Islam and to marry their kidnappers during their time in captivity.

Boko Haram has kidnapped thousands of other people during its eight-year insurgency aimed at creating an Islamic caliphate in north-eastern Nigeria.

More than 30,000 others have been killed, the government says, and hundreds of thousands have been forced to flee from their homes.

Boko Haram at a glance:

• Founded in 2002, initially focused on opposing Western-style education – Boko Haram means “Western education is forbidden” in the Hausa language
• Launched military operations in 2009
• Thousands killed, mostly in north-eastern Nigeria, hundreds abducted, including hundreds of schoolgirls
• Seized large area in north-east Nigeria, where it declared caliphate
• Joined so-called Islamic State, now calls itself IS’s “West African province”
• Regional force has now retaken most of the captured territory
• Group split in August after rival leaders emerged

– BBC