TAGAB VALLEY, Afghanistan (AP) — Hundreds of French and Afghan troops on Sunday pushed into a hostile valley in eastern Afghanistan where militants launch quick attacks, then disappear into hillside villages. The mission: secure the area for a planned bypass road around the Afghan capital to move supplies from neighboring Pakistan.

About 700 French troops, joined by 100 Afghan soldiers, moved into the Tagab valley before dawn with more than 100 armored vehicles. U.S. and French attack helicopters roared overhead as insurgent snipers fired from the roofs of houses onto the advancing column of vehicles, according to a reporter for The Associated Press traveling with the French troops.

NATO forces have bases in the wide-bottomed valley, but they have had difficulty securing the mountainous area connected by small footpaths. Just 30 miles (50 kilometers) from Kabul, the valley is seen as a launching pad for attacks in the capital. In a neighboring valley last year, militants killed 10 French troops.

"The objective is to clear the valley to be able to build the road, and checkpoints financed by the European Union," said Col. Francis Chanson, head of France's 3rd Marine Infantry Regiment.

Construction has already begun in one of the safer parts of eastern Kapisa province.

The offensive, called "Operation Avalon," was led by the 3rd Marine Infantry Regiment, with elements of the 2nd Infantry Regiment of the Foreign Legion.

Intelligence officers estimated there were 60 to 80 armed insurgents directly on the column's path, said Capt. Vincent, who went only by his first name because of French Foreign Legion anonymity rules.

Insurgents could be seen firing on the column of vehicles and then sliding back into houses before attack helicopters could fire back. The reporter witnessed a man dressed like a farmer fire a rocket-propelled grenade at 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 later in the afternoon. There were no casualties immediately reported.

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 tied to the militant network run by Jalaluddin Haqqani, NATO said. It did not specify how many were killed.

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