Over 60 women and girls have managed to escape their Boko Haram captors in Nigeria, security sources confirm.

Abbas Gava, described as a "local vigilante" working for government authorities, told Agence France Presse (AFP) yesterday that "63 of the abducted women and girls had made it back home" late on Friday evening.

Although some reports suggest the women are among those abducted from a school in Chibok, Borno State, on April 14, Gava insisted that they were instead part of a group kidnapped from Kummabaza village, also in Borno, in June.

The girls allegedly found an opportunity to escape when their captors left to undertake a further attack.

"They took the bold step when their abductors moved out to carry out an operation," Gava told AFP.

"We don't have the details of their escape yet, but we believe God gave them the opportunity at the time the insurgents came in their large numbers to attack Damboa where about 12 soldiers, five policemen, over 50 Boko Haram members and unspecified number of civilians were killed yesterday [Saturday]."

A "high-level security source" later confirmed the escape, though there has been no official statement as yet from the Nigerian government, which has faced significant criticism for its failure to stop Islamic extremism across the northern parts of the country.

Over 200 girls taken from Chibok remain missing, despite repeated calls from the international community for their release.

Boko Haram's leadership is demanding the exchange of some of its top militants in return for the girls, but negotiations have so far been rejected by the government.

The militant group – whose name translates as 'Western education is forbidden' – is responsible for thousands of deaths since its uprising in 2009, including over 2,000 this year alone. Members have declared intent to cleanse the country of Christians, eradicate Nigerian democracy and replace it with an Islamic state guided by Sharia law.