Hundreds of French and Afghan troops pushed into a volatile valley east of the Afghan capital Sunday in an attempt to gain control of an area that has long been a haven for militants who launch quick attacks and then fade back into hillside villages.

The force of about 700 French and 100 Afghan soldiers launched the offensive into the Tagab valley before dawn, one part from the north and another from the south, according to Col. Francis Chanson, head of the French marine infantry regiment.

Just 30 miles from Kabul, the Tagab valley is seen as a launching pad for attacks in the capital. The area also needs to be secure for a planned road that would bypass the capital for moving supplies from neighboring Pakistan to the north of the country, Chanson said. Construction has already begun in one of the safer parts of eastern Kapisa province.

NATO forces have bases in the valley, but have had difficulty securing the mountainous area connected by small footpaths. In a neighboring valley last year, militants killed 10 French troops.

The joint force moved in with more than 100 armored vehicles as U.S. and French attack helicopters roared overhead. Insurgent snipers fired from the roofs of houses onto the advancing column of vehicles, according to an AP reporter traveling with the French troops.

Intelligence officers estimated there were 60 to 80 armed insurgents directly along the column's path, said Capt. Vincent, who according to French Foreign Legion rules can only be identified by his first name.

No casualties were immediately reported. Insurgents could be seen firing on the column of vehicles and then sliding back into houses before attack helicopters could fire back.

The AP reporter saw one man dressed like a farmer fire a rocket-propelled grenade at the French troops, then drop his weapon and run into a field where he disappeared into a group of villagers.

The forces retaliated with sporadic artillery shelling and helicopter-borne missiles as the fighting intensified in the afternoon.

Separately in the eastern province of Paktika, which borders Pakistan, a joint NATO and Afghan force killed "a group of militants" while pursuing a commander linked to a militant network run by Jalaluddin Haqqani, NATO said.

The force came under fire during an assault on a building in the hills of Sarobi district, and returned fire, NATO said, adding that the militants were killed both inside and outside the building. It did not specify how many were killed.

Two suspected militants were arrested during the operation, while the joint forces seized bomb-making materials, rocket-propelled grenades and assault rifles as well as communications equipment, it said.