AFP - Three French soldiers were killed in a lightning storm during a nighttime operation targeting Taliban bomb squads in a valley east of Kabul, the French military said Sunday.

One man was killed by lightning and two others drowned, said Admiral Christophe Prazuck, spokesman for the French armed forces general staff, taking the toll among the French military in Afghanistan to 34.

Th More..ey were part of a 250-troop operation hunting fighters responsible for planting roadside bombs in Kapisa Province east of Kabul, the spokesman said.

The joint French and Afghan operation, taking place by night in the Afghanya Valley some 50 kilometres (30 miles) from Kabul, was suspended after a first soldier was struck dead by lightning, according to Prazuck.

Another soldier was swept off a footpath by a flooding river while medics attended to the lighting victim, and a third was carried off as he tried to rescue his comrade.

"The pair were found drowned at dawn," said Prazuck.

The victims were a flight sergeant and a corporal of the 13th parachutist special forces regiment, and an airman of the 3rd marine infantry regiment.

All three were stationed at the Nijrab forward operating base in Kapisa Province, where their bodies were evacuated by helicopter, said a French military spokesman in Kabul.

President Nicolas Sarkozy's office issued a statement saying the head of state "shares in the pain of the families and their loved ones. He offers them his sad condolences."

"They paid with their lives to honour France's commitment to bring peace and security to the Afghan people," said the statement, stressing France's "determination to work to restore peace and development in Afghanistan."

Defence Minister Herve Morin, who visited the Nijrab base earlier this month, voiced his "great emotion" at the men's deaths.

In a separate incident, a soldier with the French Foreign Legion was killed when an armoured vehicle in which he was travelling fell into a ravine on Sunday, the French military and the Elysee Palace in Paris said.

Five other legionnaires were injured in the accident, in the Surobi district, which came as they were returning from Kabul to their forward operating base at Tora.

France has now lost 35 soldiers in Afghanistan, where it has 2,900 French troops in the NATO-led coalition battling Taliban guerrillas and training Afghanistan's national security forces.

Paris pulled out most of its special forces from Afghanistan in 2006, but around 60 operatives remain stationed in the country on commando training and intelligence missions, Prazuck said.

Afghanistan had been hit hard by a renewed Taliban insurgency, which has paralysed a Western-backed reconstruction drive, cost the lives of thousands of people, and bogged NATO and US troops down in a nearly eight-year conflict.

This year has been the deadliest for the 100,000 foreign troops in Afghanistan since US-led forces ousted the Taliban from Kabul following the September 11, 2001 attacks in the United States.