Two French servicemen were killed on Thursday when an Afghan army soldier shot at them deliberately while their unit was engaged in a support mission for Afghanistan's forces in the Tagab valley, President Nicolas Sarkozy's office said.

The deaths bring the total number of French soldiers killed in Afghanistan to 78 since France joined the NATO-led operation in 2001.

Sarkozy's office stressed France's commitment to the NATO-led International Security Assistance Force in Afghanistan, according to a statement. Prime Minister Francois Fillon condemned the cowardly assassination in a separate statement.

(Reporting By Daniel Flynn Editing by Maria Golovnina)