Updated

U.S. and Afghan troops backed by warplanes recaptured a town from suspected Taliban rebels in heavy fighting, as violence across the south left as many as 35 militants dead, officials said Saturday.

The government, meanwhile, announced a shake-up of the country's top police commanders after the worst anti-foreigner riots in years shook the capital.

The U.S. and Afghan forces retook the southern town of Chori on Friday in heavy fighting that left as many as 20 militants dead, said Defense Ministry spokesman Gen. Zahir Azimi. The bodies of 15 insurgents were scattered around the town.

CountryWatch: Afghanistan

Hundreds of militants attacked the town in Uruzgan province Wednesday, forcing local security forces to flee. While rebels having been increasing attacks in recent weeks, it is unusual for them to manage to successfully control a large chunk of territory for days.

U.S. military spokesman Sgt. Chris Miller said the Afghan and U.S. troops suffered no casualties and confirmed that police had resumed control of the area.

In other violence, militants attacked a police station Friday in Miana Shien town, Kandahar province, sparking clashes that left 12 militants dead and 17 people wounded, including four police, said Dawood Hamadi, the provincial spokesman.

In neighboring Helmand province Friday, coalition warplanes bombed militants loading munitions from a cave hide-out onto a truck, the U.S. military said in a statement. The number of militant casualties was still being assessed, it said.

Also in Helmand on Friday, U.S. troops killed three militants in a gunbattle, said coalition spokesman Maj. Quentin Innis.

In the country's northern Baghlan province, gunmen shot dead an Afghan aid worker in his home Friday, said Mohammad Qasim Amirzai, a deputy local police chief. The motive for the attack was unclear.

An upsurge of fighting, particularly in southern regions where the Taliban are strongest, has left over 400 people, mostly militants, dead since mid-May. Violence has also wracked Kabul, with rioters last Monday attacking foreigners after a deadly road crash blamed on U.S. troops.

Police in the capital have been criticized for taking too long to control the unrest and on Saturday, the government announced that the city's police chief would be replaced, along with 85 other police generals across the country.

A Ministry of Interior statement said the new commanders "have been appointed to improve and maintain the security as part necessary reforms in the ministry."

A spokesman for the ministry declined to say whether the shake-up — the largest in the force since the fall of the Taliban in 2001 — was linked to Monday's riot, in which up to 20 people were killed as protesters rampaged through the city shouting "Death to America!"

Afghan investigators had been scheduled to start an inquiry Saturday into the traffic accident that sparked the unrest, but police Maj. Gen. Abdul Wakil said the probe had been delayed for a day because of unrelated matters. The U.S. military is carrying out its own probe.

The riots surprised many in the international community here and raised fears that tolerance of their presence was waning amid frustration over civilians killed during Afghan and coalition operations and the slow pace of postwar reconstruction.

Insurgents have tried to capitalize on that resentment, and on Saturday Arab broadcaster Al-Jazeera, quoted Gulbuddin Hekmatyar, a renegade former premier wanted by the United States, as purportedly threatening new violence against U.S. troops.

"(The) resistance is not weak. All the Afghan people insist on taking revenge and wish, if you stay for a longer period, to cause you more causalities," Hekmatyar said on an audiotape, according to the broadcaster, which translated his comments into Arabic.

"There is plenty of equipment. And if we carry out 100 operations a year, the costs won't exceed US$1,000. But will you be able to transfer 1,000 coffins?"

It was not immediately possible to verify if the comments were those of Hekmatyar, who is believed hiding in rugged mountains along the Afghan-Pakistan border. Sgt. Miller, the U.S. military spokesman, declined to comment on the threat.