Four northern states in Nigeria have ordered the immediate closure of schools following the abduction of hundreds of students in Katsina State.

The closure order affects schools in Kano, Kaduna, Zamfara and Jigawa states.

The Nigerian teachers’ union has also threatened to go on strike over insecurity in the country.

It says pupils and teachers are being targeted by gunmen and kidnappers.

Last week hundreds of students were abducted from the Government Science Secondary School in Kankara.

The Islamist militants Boko Haram said they carried out the abductions.

The federal government is yet to reveal the extent of discussions it is having with the abductors.

Some 333 students are still missing.