WASHINGTON — Military officers told a House oversight committee Tuesday that a U.S. commander asked them to retract a request that the Defense Department investigate substandard conditions for Afghan patients at a U.S.-backed military hospital in Kabul.

Army Col. Mark Fassl said he witnessed horrible conditions during his inspection of Dawood National Military Hospital and urged a probe, but he met resistance up the chain of command.

Fassl emailed the DoD Inspector General’s office requesting investigation, but he said he later retracted the request on orders from Army Lt. Gen William Caldwell, who at the time was the top U.S. officer in charge of the program.

Fassl, who is still in the Army, said Caldwell, a three-star general, did not want an investigation into the dreadful conditions at the facility, which the colonel described in his email.

“No hygiene capabilities for 6-months — NO soap, bleach and bacterial wipes,” Fassl wrote in an Oct. 28, 2010, email to Kenneth Moorefield, deputy inspector general. “Human waste — blood, feces, urine and wound drainage are being collected, spilled in open buckets next to patients’ beds while at the same time food is being served.”

Caldwell is now head of U.S. Army North and senior commander of Fort Sam Houston in Texas.

A slideshow of four photos, which were presented during the hearing of the House Oversight and Government Reform national security subcommittee, exemplified Fassl’s description of patient neglect. They depicted open wounds, maggots crawling from beneath patients’ skin and severe cases of gangrene.

“Personally, in my short 3½ years here, other than what I saw in Haiti, I think this is one of the most difficult things I have looked at,” said subcommittee chairman Jason Chaffetz, R-Utah, who chaired the panel.

Chaffetz said the committee collected a total of 70 photos, but that most were too gruesome to display.

Former colonels, active military leaders and a Defense auditing official gave personal testimony, adding to the timeline of alleged mismanagement, theft and corruption dating back nearly a decade at Afghanistan’s main military hospital.

The U.S. has supplied more than $150 million in medical supplies and medicine to the Afghan system since 2007, an amount that could fund a functional U.S. military hospital for three years, witnesses said.

DoD began an ongoing audit investigation of pharmaceutical processes at the hospital after revelations that the corruption at the hospital allowed Afghan leaders like former Surgeon General Zia Yaftali to embezzle an estimated $20 million over four years.

Afghan officials said they have improved their vetting system for medical vendors.

“We have seen, in the past year, accountability even in the hospital is starting to occur,” said Daniel Blair, deputy inspector general for auditing at the DoD.

But Blair said there are still problems. He described vendors who fail to live up to contract requirements, and several supply depots that cannot account for a number of pharmaceuticals, pointing to possible theft.