Overseas military operations will be more and more difficult but its risks must be dealt with, a top French military official said in an interview to be published Saturday.

"The time of easy overseas operations is over," General Jean-Louis Georgelin, chairman of the joint chiefs of staff, told Le Figaro newspaper, after 10 French soldiers were killed and 21 wounded in an attack by insurgents in Afghanistan Monday.

"We're witnessing a return to war operations. Overseas operations will be more and more difficult," he said, adding it was normal that Monday's tragedy was causing so much distress.

"It also reminds us that sending troops overseas has risks and that they must be dealt with," he said, adding: "We're facing elusive terrorist movements and no longer regular armies whose actions can be clearly identified."

The deaths — France's worst military loss in 25 years, and the highest NATO death toll on the ground in Afghanistan since the conflict began in 2001 — have brought home the fact that French troops are on the frontline of the US-led "war on terror."

President Nicolas Sarkozy's decision in April to send 700 additional troops to Afghanistan — in response to NATO calls for reinforcements — bringing the number of French soldiers there to nearly 3,000, is hugely unpopular.

Polls show a large majority of French opposed the move, with many fearing France is getting bogged down in an unending war whose aims appear unclear or unattainable.