Rebel fighters attacked U.S. troops and fired rockets at American helicopters in a skirmish in southern Afghanistan (search), the military said Wednesday.

No casualties or damage were reported from the firefight on Monday near Deh Rawood, 250 miles southwest of the capital, Kabul, spokesman Maj. Scott Nelson said.

Four insurgents armed with assault rifles and machine guns opened fire on American troops, he said.

"The anti-coalition militants fired rocket-propelled grenades at the AH-64 (helicopters) providing close air support," Nelson said. "The AH-64s returned fire and the (militants) broke contact."

The incident came the same day that a Blackhawk helicopter carrying soldiers from the U.S.-led coalition made a "hard landing" near Deh Rawood, where there is a small American base.

A Taliban (search) spokesman claimed on Monday that the militia's fighters shot the helicopter down with a rocket, killing several American soldiers.

But the military said it was a "non-hostile incident" and that while the helicopter was damaged, there were no injuries.

Deh Rawood is in Uruzgan province, part of a swath of southern and eastern Afghanistan where Taliban-led militants have sustained a stubborn insurgency since their ouster in 2001.

Attacks have been less frequent in the north, where NATO (search) troops are expanding their operations ahead of Oct. 9 presidential elections. Campaigning for the polls began Tuesday.

A spokesman for the force said one of its patrols came under fire from Afghan government militia troops in a mixup on Friday over a weapons cache, but no injuries were reported.

Two Apache helicopter gunships were sent to reinforce the NATO soldiers, which confiscated the weapons near Ghorband, north of Kabul, spokesman Lt. Cdr. Ken Mackillop said.

The weapons were later returned to the local militia division after talks involving the U.S. ambassador, Mackillop said.

That particular division is to be disarmed this week under a program to dismantle all the country's feuding militias.