Federal investigators are examining allegations of criminal misconduct related to $6 billion worth of contracts for equipment and services needed in Iraq and Afghanistan, a senior Pentagon official said Thursday.

The financial scope of the inquiries was provided during a congressional hearing at which Defense Department representatives were criticized for moving too slowly to deal with a growing number of cases of contract fraud and abuse.

Following the testimony from Thomas Gimble, the Pentagon's deputy inspector general, members of the House Armed Services Committee questioned whether a "culture of corruption" had consumed the military's system for buying the gear the troops need to fight.

No, said the witnesses. In addition to Gimble, they included Lt. Gen. N. Ross Thompson, a top Army acquisition official, and Shay Assad, director of defense procurement.

They attributed the impropriety to a handful of "bad apples," a lack of stringent accounting controls, too few properly trained contracting personnel and the demands of wartime operations.

"This sickens me, when there is even one case of an officer or a noncommissioned officer who is involved in case of fraud or accepting a bribe," Thompson said. But he said there was no "widespread conspiracy."

Added Assad: "We did not properly train our officers and enlisted (personnel) to work in the environment."

But Gimble's public remarks, which came after committee members received a classified briefing on the investigations, did little to assure the lawmakers that the problems are not deeper.

Gimble said his office has 225 people working on 90 investigations and 29 audits stemming from the hundreds of billions dollars spent on the wars thus far.

About half the investigations are for procurement fraud, a category that includes undelivered or defective products, overcharges and false claims, according to Gimble's testimony.

An additional 26 inquiries involve public corruption, which covers bribery and conflicts of interest, Gimble said. There are 16 linked to the theft of money or property and violations of U.S. export rules.

Just over 50 investigations originated in Iraq and 22 started in Kuwait, the site of an Army contracting office that service officials had previously said was a source of many flawed contracts.

Targets of the investigations include military and civilian government personnel, and contractors from the United States and other countries, according to Gimble's testimony.

Agents from the inspector general's office, FBI, Army, Air Force and Navy criminal investigative services, the Internal Revenue Service and Scotland Yard are engaged in the investigations.

Democrats and Republicans on the committee, often divided over the direction of the Iraq war, were united in their displeasure over what Gimble told them.

"This is a sad day for the United States," said Rep. Duncan Hunter of California, the committee's top Republican. "Dishonesty is not a function of manning levels."

Assad pointed to the formation in early 2005 of a joint contracting command for Iraq and Afghanistan as a positive step toward more visibility over the huge amounts of money are spent. The command has close to 200 contracting officers at locations in Iraq and Afghanistan.

In a separate but related subject that also is under investigation, an Iraq expert from the Defense Department acknowledged that oversight of American weapons bound for Iraqi forces have been so lax that no one knows for certain where all the guns and ammunition wound up.

"There was an imperative to get this equipment out to the fighting forces as quickly as possible," said Peter Velz, a foreign affairs specialist for Iraq.

Velz said the U.S.-led command training Iraqi forces did not have enough people in Iraq to properly catalog the thousands of weapons flowing into the country. As a result, the Pentagon does not know if the number of weapons that were destined for the Iraqis "were in fact transferred," he said. The issue first surfaced in May when Pentagon officials learned that Turkish officials were concerned that American-issued weapons were being used in violent crimes in their country. In July, Defense Secretary Robert Gates sent the Pentagon's top lawyer, William Haynes, to Turkey to hear the concerns.

Pentagon Inspector General Claude Kicklighter was subsequently directed to investigate the failures that led to the distribution problems. Gimble said that inquiry is one of his office's "highest priorities."

Although the subjects are serious ones, only about a dozen of the committee's 61 members attended the hearing. By the time it ended, the witnesses outnumbered the lawmakers. Just the committee chairman, Rep. Ike Skelton, D-Mo., and Rep. Carol Shea-Porter, D-N.H., remained.