Hours before flying to Washington for talks with President Bush (search), Afghan leader Hamid Karzai demanded greater control Saturday over American military operations in his country and called for vigorous punishment of any U.S. troops who mistreat prisoners.

He also said he wants the United States (search) to hand over all Afghan prisoners still in U.S. custody.

In a volatile southern province, meanwhile, a U.S. soldier was killed and three were wounded in the latest in a string of attacks launched by loyalists of the ousted Taliban (search) regime.

Speaking to reporters before his first visit to the United States since he was installed in December as Afghanistan's first democratically elected president, Karzai demanded more say over operations by the 16,700 U.S. troops still in the country, including an end to raids on the homes of Afghans unless his government was notified beforehand.

"No operations inside Afghanistan should take place without the consultation of the Afghan government," he told reporters.

Karzai — seen by his critics as an American puppet — issued the tough statement after fresh reports of prisoner abuse by American forces at Bagram, the main military prison north of Kabul, and anti-U.S. riots that broke out across the country earlier this month, leaving at least 15 people dead.

The unrest was triggered by a Newsweek magazine report, later retracted, that the Quran was defiled by interrogators at the U.S. prison at Guantanamo Bay, Cuba, and likely further fueled by long-standing complaints of heavy-handed search operations and the deaths of civilians in U.S. operations in Afghanistan.

There were fears a report in Friday's New York Times, based on the Army's criminal investigation into the December 2002 deaths of two Afghans at Bagram, could re-ignite anti-American manifestations.

Karzai said he was "shocked" by allegations of prisoner abuse by poorly trained U.S. soldiers at Bagram and vowed to raise the issue during his four-day U.S. visit that begins Sunday.

"We want the U.S. government to take very, very strong action to take away people like that (who) are working with their forces in Afghanistan," Karzai said. "Definitely ... I will see about that when I am in the United States."

Responding to the abuse allegations, Col. James Yonts, the U.S. military spokesman in Afghanistan, said: "The command has made it very clear that any incidents of abuse will not be tolerated."

In Washington, White House spokesman Trent Duffy said the president was "alarmed by the reports of prisoner abuse," and wants them thoroughly investigated. Duffy said seven people were being investigated about abuse at Bagram.

The Times' allegations of maltreatment were supported by Human Rights Watch, a New York-based watchdog, which said that at least six detainees in U.S. custody in Afghanistan have been killed since 2002.

"U.S. forces in Afghanistan were involved in killings, torture and other abuses of prisoners," it said in a statement.

"These crimes, known to senior officials in the military and Central Intelligence Agency, have not still been adequately investigated or prosecuted."

In December, Pentagon officials said that eight deaths of detainees in Afghanistan — including the two mentioned in the Times report — had been investigated since mid-2002. Hundreds of people were detained during and after the campaign by U.S.-led forces to oust the hardline Taliban regime in late 2001.

After the outcry over abuse at the Abu Ghraib prison in Iraq, the military also initiated a review of its detention facilities in Afghanistan and later said it had modified some of its procedures, although the review's findings have not been made public.

Also, an Italian aid worker kidnapped in Kabul spent her sixth day in captivity on Saturday, still with no clear word on her fate.

Taliban-led rebels kept up assaults in the south and east of the country. A roadside bomb killed one U.S. soldier and wounded three others as they patrolled in an armored vehicle in Zabul province, the U.S. military said. A purported spokesman for the Taliban claimed responsibility.

Brig. Gen. Greg Champion, a deputy commander of Combined Joint Task Force 76, said in a telephone interview Friday from his headquarters at Bagram, that the recent increase in insurgent violence was due mainly to a more aggressive approach by American and Afghan forces.

"We have not taken a posture of waiting" for the Taliban to begin their usual spring offensive, he said. Instead, U.S. and Afghan forces have been "going on our own offensive."

A mine explosion in southern Kandahar province wounded four Afghan soldiers, while a two-hour gunbattle between Taliban rebels and Afghan forces in Zabul left two insurgents dead, officials said.

In Ghazni province, four people driving to a wedding were killed and four others were wounded when an old land mine exploded under their vehicle, said police chief Gen. Abdul Rahman Sarjang.