Chibok abductions in Nigeria: 'More than 230 seized' Published duration 21 April 2014

media caption A week after the attack, footage has emerged from inside the school, as Will Ross reports

Some 190 Nigerian schoolgirls remain missing after being abducted last week, their head teacher has told the BBC - far more than the official figure.

Asabe Kwambura said the parents of 230 girls had reported them missing but 40 had managed to escape.

Earlier, a local state governor said that about 77 of the teenagers had not been accounted for.

Islamist group Boko Haram is suspected to be behind the kidnapping but has not issued any statement.

Some 1,500 people are believed to have been killed in attacks blamed on Boko Haram this year alone.

The group, whose name means "Western education is forbidden", is fighting to establish Islamic law in Nigeria. It often targets educational establishments.

According to the AP news agency, parents from the school in the town of Chibok told Borno State Governor Kashim Shettima when he visited on Monday that 234 girls had been abducted.

When news first emerged of the kidnap last Tuesday, initial reports said more than 200 students had been seized but state officials soon downgraded the numbers, saying the correct figure was about 130.

The students were about to sit their final year exam and so are aged 16-18.

Ms Kwambura told the BBC Hausa service that about 43 had fled their captors.

"None of these girls were rescued by the military, they managed to escape on their own from their abductors," she said.

Asked about the conflicting reports on the number of students kidnapped, she said: "Only reports that come from us is the truth and based on the register we have on paper."

She has previously called on the kidnappers to "have mercy on the students".

Before visiting Chibok on Monday, the Borno state governor said that eight more girls had escaped over the weekend, meaning a total 52 had fled.

Mr Shettima did not give details of how the girls had escaped, for security reasons.

The confusion over the numbers comes after the military last week said that all but eight of the students had been rescued before withdrawing its claim a day later.

It is thought that the militants took the girls to the Sambisa forest near the Cameroonian border.

Parents and vigilante group have gone there to help search for the teenage girls.

Borno, Yobe and Adamawa states in north-east Nigeria have been under emergency rule since last May.