Boko Haram: Nigeria seals border with Cameroon

Following waves of attacks by Boko Haram Islamists, Nigeria has sealed a portion of its northeastern border with Cameroon to block the movement of insurgents and other criminal groups.

The closure has been imposed in Adamawa state, one of three states in the northeast placed under emergency rule in May.

The military has launched a major offensive in the area aimed at crushing the Islamist uprising, which has killed thousands since 2009.

Nigeria claims that the Islamists have set up bases in sparsely populated areas of its northeastern neighbours - Cameroon, Chad and Niger - and flee across the border after staging attacks to avoid military pursuit.

"What I did was completely seal off the borders, no going in, no going out," said Brigadier General Rogers Iben Nicholas, the top military commander in Adamawa.

He said the measure had been in place since Monday and that it has already curtailed "the influx of miscreants (and) terrorist elements" into Nigeria.

"Other security agencies like the customs, immigration services, have been told. Our soldiers and police are also there working together to ensure that nothing crosses into Nigeria," Nicholas said.

Adamawa has been less hit by violence than the other affected states, Borno and Yobe, but it is thought to provide key transport routes for the insurgents.

Despite the state of emergency, Boko Haram has continued to carry out attacks in the northeast, with more than 300 people killed already this year.