US Special Forces step up hunt for Ugandan warlord Joseph Kony

US President Barack Obama has ordered a sharp increase in Special Forces deployed to Uganda and sent military aircraft there for the first time in the ongoing effort to hunt down warlord Joseph Kony across a broad swathe of central Africa.

At least four CV-22 Osprey aircraft will arrive in Uganda this week, along with refuelling aircraft and 150 Special Operations airmen to fly and maintain the planes, according to Amanda Dory, deputy assistant secretary of defence for African affairs.

The White House began to notify Congress, under the War Powers Act, of the new deployments as they began on Sunday night. Dory and other officials emphasised that the Ospreys would be used for troop transport and that the rules of engagement for US forces remained the same as for about 100 Special Operations troops that Obama sent to help find Kony in October 2011.

US personnel are authorised to "provide information, advice and assistance" to an African Union force tracking Kony and his organisation, the Lord's Resistance Army (LRA), across Uganda, the Central African Republic, South Sudan and Congo. While combat-equipped, they are prohibited from engaging LRA forces unless in self-defence.

The new War Powers Act notification sets the approximate total for all US forces in Uganda at 300.

Kony, whose forces have spent years attacking central African villages, mutilating civilians and stealing children, has been indicted by the International Criminal Court. His organisation is thought to have been decimated in recent years through military action and defections.