Great Britain will contribute troops to support U.N. and African Union peacekeeping operations in Somalia and South Sudan in order to counter terrorism and mitigate migration, Prime Minister David Cameron said on Monday.

“Our commitment to peacekeeping operations will help to alleviate serious humanitarian and security issues in Somalia and South Sudan,” he said in a statement.

About 70 British troops will support the U.N. and A.U. mission in Somalia to promote stability and tackle the Islamist terrorist organization al-Shabab. They will provide medical, logistical and engineering expertise to an A.U. forces.

Cameron offered a further 250 to 300 troops to help with engineering work, combat training and take an advisory role in South Sudan. The humanitarian crisis has been worsening in South Sudan since a civil war broke out in December 2013. Escalating conflict has displaced 2.2 million people and left 4.6 million people severely food insecure, according to the U.N. humanitarian office.

At the moment, the U.K. has some 280 troops deployed with the U.N. mission in Cyprus.

Cameron will officially announce the plan at a U.N. peacekeeping session on Monday that is to be co-hosted by U.N. Secretary-General Ban Ki-moon and U.S. President Barack Obama.

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Write to Mark Rivett-Carnac at mark.rivett-carnac@timeasia.com.