The U.S. military says a man dressed in an Afghan army uniform has shot and killed two U.S. soldiers outside a top security prison near Kabul.

Military spokesman, Major Sheldon Smith says the gunman wounded two other American soldiers in the shooting Sunday.

The spokesman says the gunman was shot dead by Afghan troops at the prison. The motive for the attack is unclear.

Earlier, Afghan officials said a remote-controlled roadside bomb killed five policemen in Ghazni province in eastern Afghanistan.

Authorities also said a suicide bomber detonated explosives near police in the western province of Farah, killing only the bomber.

In the past year, Taleban insurgents have dramatically increased their attacks against Afghan authorities and U.S.-led coalition troops.

U.S.-led forces pushed the Taleban from power in late 2001 following the September 11, 2001 terrorist attacks.

Some information for this report was provided by AFP and AP.