© Rahmat Gul/APA wounded man talks with a security guard at the scene of a bomb explosion in Jalalabad, Nangarhar province, Afghanistan on Dec. 29, 2011.
Kabult, Afghanistan - An Afghan investigative commission accused the American military Saturday of abuse at its main prison in the country, repeating President Hamid Karzai's demand that the U.S. turn over all detainees to Afghan custody and saying anyone held without evidence should be freed.

The demands put the U.S. and the Afghan governments on a collision course in an issue that will decide the fate of hundreds of suspected Taliban and al-Qaida operators captured by American forces. Members of the Afghan investigation said U.S. officials told them that many of those militant suspects were taken based on intelligence that cannot be used in Afghan courts.

The escalating controversy and demands by Karzai appeared to be the most recent in a series of exercises in political brinksmanship, as the president tries to bolster his negotiating position ahead of renewed talks for a Strategic Partnership Document with America that will determine the U.S. role in Afghanistan after 2014, when most foreign troops are due to withdraw.

Among the conditions that Karzai has set is an end to night raids by international troops and complete Afghan control over detainees.

The dispute that has unfolded in recent days mirrors many of the thorny issues surrounding the controversial U.S. detention center at Guantanamo Bay. There, as at the prison in Afghanistan, American forces are holding many detainees without charging them with a specific crime or presenting evidence in a civil court.

Detainees interviewed during two visits to the U.S.-run portion of the prison outside Bagram Air Base north of Kabul complained of freezing cold, humiliating strip searches and being deprived of light, according to Gul Rahman Qazi, who led the investigation ordered by Karzai.

Another investigator, Sayed Noorullah, said the prison must be transferred to Afghan control "as soon as possible," adding that "If there is no evidence ... they have the right to be freed."

U.S. Embassy spokesman Gavin Sundwall said Saturday that American officials only received the commission's report after its press briefing. He said the U.S. investigates all allegations of prisoner abuse.

"We will certainly take seriously the report and study it," he said. He added that the U.S. is committed to working with the Afghan government on a joint plan to turn over detainees "in a responsible manner."

Karzai on Thursday abruptly demanded that the U.S. military turn over full control of the prison, officially known as the Parwan Detention Center but generally referred to as the Bagram prison, within a month. A spokesman for the president said Saturday that he made the announcement in response to the investigation team's report.

The president's demand for full control of the prison so soon took many by surprise, since the U.S. and Afghan governments had been working on a gradual timetable for transferring responsibility for the prison over the next two years.

Karzai is walking a fine line. Although he routinely plays to anti-American sentiment in Afghanistan by denouncing the U.S., he needs America's military and financial strength to back his weak government as it battles the Taliban insurgency.

Some U.S. officials have argued that freeing some of the detainees at the facility known as Bagram could send hardened Taliban and al-Qaida militants back out to fight the government and coalition troops, according to Qazi.

Officially, U.S. and Afghan militaries jointly run the facility, but the Afghan side controls a small portion with about 300 detainees whose cases are slated to be tried by Afghan judiciary. The U.S. military runs the larger portion of the prison.

Qazi, who led the ad hoc investigation of the Independent Commission for Overseeing the Implementation of the Constitution, said U.S. prison officials told only about 300 of the nearly 3,000 detainees had legal cases against them.

He said he was told that that 2,700 others were suspected Taliban who were captured using intelligence that could not be used in a court.

"The foreign friends told us they are held based on the rules of the battlefield, and they are dangerous and cannot be set free," Qazi told reporters Saturday.

Prison officials also made it clear that many of those being held had no evidence against them that would hold up in court, said Abdul Qader Adalatkhwa, the deputy leader of the commission.

"The Americans told us that according to their rules and regulation, whenever they detain somebody, after taking photos of the evidence at the site, they eliminate all the evidence of the site - bullets, weapons, any other evidence," Adalatkhwa said.

"So this is their concern," he said. "That when they hand over the detainees to the Afghan side, because of the differences in the civilian Afghan system and the U.S. (military) system, most of these people might get freed."

Nevertheless, the commission repeated Karzai's demand of full Afghan custody of all prisoners as soon as possible, though it did not set a deadline.

"Inside Afghanistan, having a prison run by foreigners is not allowed with the respect of Afghan constitution," Qazi said.

Besides Afghan militant suspects, the prison near Bagram also holds foreign al-Qaida suspects from several different countries captured in what the U.S. considers battlefield conditions.

It's unclear what would happen to those foreign suspects if they were turned over to Afghan custody.