Nigerian teachers went on strike and staged rallies nationwide on Thursday in protest against the kidnapping of more than 200 schoolgirls by the Islamist Boko Haram sect and the killing of nearly as many teachers during its insurgency.

Boko Haram gunmen stormed a school outside the remote north-eastern town of Chibok on April 14, carting some 270 girls away in trucks. More than 50 have escaped but at least 200 remain in captivity, as do scores of other girls kidnapped previously.

National Union of Teachers President Micheal Alogba Olukoya said Boko Haram had killed 173 teachers over five years. In Maiduguri, capital of the northeastern state of Borno where the insurgency is most intense, around 40 teachers marched to the office of Governor Kashim Shettima