Lt. Col. Douglas Lefforge said the three were part of a 10-man "enemy element" observed Wednesday night near the US base in Asadabad, capital of eastern Kunar province near the Pakistan border.

"The firebase fired 120mm mortar illumination rounds as a warning, then fired high explosive rounds, killing the estimated three personnel," Lefforge said in an e-mailed statement from Bagram Air Base, headquarters of US-led coalition forces in Afghanistan.

The rest of the suspected insurgents fled the area and a coalition ground patrol was dispatched to investigate further, Lefforge said.

No coalition casualties were reported.

Near Asadabad last week, coalition forces called in a B-52 bomber and two fighter jets to pound insurgents who fired two rockets at the US base. None were killed or wounded.

Elsewhere, insurgents fired three rockets at another US base to the southeast in Orgun, a small town in Paktika province, Lefforge said.

The rockets fell harmlessly like scores of others over the last year. A coalition patrol deployed after the attack found the launch site, but none of the attackers.