Members of the Boko Haram Islamist terrorist group have allegedly kidnapped at least 200 girls from a school in northeastern Nigeria's Borno state, according to reports.

Parents of the girls told the BBC that attackers arrived at the school in Chibok and forced the teenagers at gunpoint on to four lorries.

Boko Haram, which has been conducting an armed campaign to establish an Islamic state in northern Nigeria, is also thought to be responsible for a series of attacks that left at least 120 civilians dead last week.

The group, whose name translates as "Western education is sinful", had attacked a teacher training college in Dikwa, Borno state. Five people were killed and an unsp[ecified number of women kidnapped before the assailants burnt down the library and fled.

Amnesty International estimated that 1,500 civilians had died since the beginning of the year in Boko Haram assaults but the group blamed the Nigerian army for many of the deaths. After a Boko Haram attack in March, troops army killed 600 people in Maiduguri, Amnesty said.

Boko Haram is behind several massacres in the area. Nigeria's own relief agency estimated that 250,000 people had fled their homes because of fighting in the region.