Fighters loyal to several regional warlords stormed a remote provincial capital and forced the governor to flee, one of the group's leaders and a government official said Friday. At least 10 people were believed killed.

The violence presents a fresh security threat for President Hamid Karzai (search), whose authority is already sapped by factional fighting across a swath of northern and western Afghanistan as well as a spreading Taliban-led insurgency.

Clashes broke out late Thursday in Chagcharan, a small town that is the capital of western Ghor province, 220 miles west of the capital Kabul.

Din Mohammed Azimi, Ghor's deputy governor, said the governor had fled for either Herat or Kabul on Thursday afternoon.

Azimi, who said he was speaking from a village a few miles to the north of the city, said at least 10 of his men were killed and that more than 1,500 fighters were preparing a counterattack.

Ghulam Yahya, a former Ghor police chief who is now one of the warlords opposed to the governor, said he knew of only one person killed, but it was not clear if he was referring only to casualties on his side.

The fighting follows weeks of tension between allies of the provincial military commander, Ahmad Murghabi, and rival tribes over positions in the local administration.

Azimi said a group of rival factions led by Rais Salam launched the attack after rejecting an offer of control of four government departments, including police and intelligence.

He said a delegation from the Kabul government led by Alam Rasekh, an adviser to Karzai, had left Chagcharan on Wednesday.

Once the fighting broke out, Azimi said he appealed in vain to Defense Minister Mohammed Fahim and other officials in Kabul.

"They promised to help but nothing came. The central government is very weak, it's useless," he complained, also calling for NATO and the U.S. military to send troops.

Government officials in Kabul were not immediately available.

Yahya described the battle as a "popular uprising," and said a council of tribal leaders would now decide how to organize the province's affairs.

"I'm chief of police and Raise Salam has taken over the military headquarters," Yahya said. "We didn't inform Kabul."

Karzai, who returned Friday from a trip to the United States, has vowed to disarm the warlords who still control most of the country more than two years after the fall of the Taliban.

But footdragging by powerful regional leaders such as Herat Gov. Ismail Khan and Uzbek strongman Abdul Rashid Dostum (search) means only a few thousand of the official total of 100,000 irregular fighters have given up their weapons so far.

Karzai was forced to divert hundreds of troops from the new U.S.-trained Afghan National Army to western Herat and to the northern province of Faryab earlier this year to quell fighting between warlord factions.

Factional tension has also wracked Sar-e-Pul and Balkh provinces, casting doubt on the country's readiness for national elections slated for September.

Further south, the United Nations has been unable to register voters in many remote areas because of the risk of Taliban attacks.

On Friday, gunmen attacked a United Nations refugee office in Kandahar city, sparking a shootout but causing no casualties, an official said.

The attackers fired at least two rockets at the office of the U.N. High Commissioner for Refugees (search), causing some damage to its walls, said Khalid Pashtun, a spokesman for the governor.

Foreign reconstruction and aid agency workers have been a favorite target of insurgents.

Eleven Chinese road contractors were shot and killed in their beds in Kunduz province last week, while five aid workers, including three Europeans, were gunned down June 2 in the remote northwest.