Obama unveiled the plan Friday which called for more troops, new legislation, improved troop training and added civilian expertise in the war in Afghanistan.

CNN: Afghan president praises Obama's new war plan

Any disruptions in training or equipment could disrupt troop rotations.

CNN: Pentagon says funding fight affecting war effort

The guns were fired by the Arbroath-based 212 Highland Battery of 105 (V) Regiment Royal Artillery, Territorial Army, augmented by the gun troop of the Glasgow and Strathclyde University Officers Training Corps.

BBC: Edinburgh Castle guns

He said there were three main aims - ensuring the troop surge works and counter-insurgency continues "full steam ahead", training the Afghan army and police, and achieving the political settlement needed "with those elements of the Taliban that want to lay down their weapons".

BBC: Cameron wants troops home from Afghanistan by 2015