At least 16 people have been killed in fighting between two rival Afghan tribes in the southeastern province of Khost, residents said on Sunday. The clash on Saturday was part of an old feud over land between rival tribes north of the city of Khost, they said. "Neither sides seems to be giving any concessions in the dispute that they have. The issue has remained unresolved and they might clash again," Nasrullah, a shopkeeper, told Reuters from Khost by satellite phone.

He said an escalation in violence was initially prevented when elders from the two tribes intervened in the rugged region north of Khost, where the U.S. special forces are also based.

But the independent Pakistan-based Afghan Islamic Press (AIP) news agency quoted Mohammad Khan Gubuz, a spokesman for the governor of Khost, as saying fighting was continuing on Sunday and many wounded men from both sides had been brought to Khost hospital.

AIP identified the rival tribes as the Balkhel and Sabari.

Witnesses told AIP the intensity of fighting was increasing and more reinforcements of men, weapons and ammunition had been sent in by the rival tribes. They said several hundred families had fled since the fighting broke out on Thursday.

Gubuz said government efforts to end the fighting had not succeeded. "We have sent delegations to them many times but they have failed," he said "We will continue our efforts."

Travelers arriving from the Khost area in the Pakistani town of Miranshah, said the fighting was over a rival territorial claim in the rugged highland region.

"The fighting started on Thursday and nine people were killed on the first day," one traveler said. "They are using all kinds of heavy weapons including cannons and rockets."

U.S. SEARCHES

Nasrullah said U.S. forces were carrying out house-to-house searches on Sunday in Dery village of Khost province, looking for arms and ammunition as part of their hunt for supporters of the ousted Taliban regime and al Qaeda network.

He said several hundred U.S. soldiers were involved in the searches, which were a continuation of the operation by U.S. forces last month in neighboring Paktia and Paktika provinces.

A number of residents and local authorities have complained about the operation, called "Mountain Sweep," saying U.S. troops have used heavy-handed tactics and had invaded their privacy.

The regions are among the most conservative in Afghanistan, where owning guns is a tradition that goes back centuries among the dominant Pashtun ethnic tribes.

During their operations U.S. forces have arrested some men from the villages whom they suspected of being members of the Taliban and al Qaeda network led by Osama bin Laden, the man accused by Washington of masterminding the September 11 attacks against the United States.

Some 8,000 U.S. soldiers and 5,000 other foreign soldiers have been based in various parts of Afghanistan since the overthrow of the Taliban regime last year.

Local reports say that several thousand Taliban and al Qaeda fighters and civilians have been killed during U.S.-led operations across the country.

U.S. forces have been frustrated by the apparent ability of the Taliban and al Qaeda survivors to hide in the mountains, flee across the border to neighboring Pakistan or blend into the local populations.

PHOTO CAPTION

An Afghan boy holds a picture for sale of the legendary Northern Alliance commander Ahmad Shah Masood who was assassinated last year by suspected al Qaeda operatives in Kabul September 8, 2002. Afghanistan will mark the one year anniversary of the Northern Alliance commander Ahmad Shah Masood's assassination on September 9. (Romeo Ranoco/Re