Insurgents launched a bold, daylight attack on an American base in southern Afghanistan, wounding three U.S. soldiers, a military spokesman said Monday.

The soldiers were hit by shrapnel when about 15 attackers opened fire on the base at Deh Rawood in Uruzgan (search) province early Sunday with rocket-propelled grenades, machine guns and AK-47 assault rifles (search), Lt. Col. Bryan Hilferty said.

American soldiers returned fire, killing one of the insurgents.

The wounded soldiers, who were flown to the main U.S. military base at Bagram (search), 250 miles northeast near the capital, Kabul, were in stable condition "and are expected to recover," Hilferty said.

It was unclear whether the attackers were affiliated to the Taliban or other groups who have mounted a wave of assaults on soldiers, government targets and aid workers across the south and east.

At least 45 people, most of them Afghan civilians, have died in violence since the country's first post-Taliban constitution was passed on Jan. 4.

American bases also have come under attack, usually from misdirected rockets launched under cover of darkness, and Sunday's raid was unusually bold.

Hilferty said Afghan authorities and the 11,000-strong U.S.-led coalition force had control all over the country, but couldn't prevent insurgents from mounting "localized" attacks.

He dismissed Sunday's daylight raid as "a sign of desperation."