France is suspending military operations in Afghanistan and may accelerate its planned troop withdrawal if the security situation does not improve, President Nicolas Sarkozy said on Friday after the killing of four more French soldiers.

Sarkozy, addressing French diplomats after an Afghan security source said four soldiers had been killed and 17 wounded by an Afghan soldier in the Taghab valley of eastern Kapisa province, confirmed that the dead were French.

I have decided to send the defence minister and the head of the armed forces to Afghanistan and until then all training operations and combat help from French forces are suspended, said Sarkozy.

If the security conditions are not clearly established then the question of an early return of French forces from Afghanistan will arise.

The shootings were the latest of several in which western soldiers have been killed by members of the Afghan security forces, undermining trust between Afghan and western troops in the run-up to the withdrawal of foreign combat troops in 2014.

It's unacceptable that our soldiers are killed by our allies. It's a difficult decision to make, he said of the suspension of French operations.

More than 2,500 foreign troops have died in Afghanistan since the NATO-led war began in 2001, and the latest killings take the French toll to 82.

(Reporting By John Irish; Editing by Brian Love)