Updated

Dozens of government watchdogs are sounding the alarm that the Obama administration is stonewalling them, in what is being described as an unprecedented challenge to the agencies they're supposed to oversee.

Forty-seven of the government's 73 independent watchdogs known as inspectors general voiced their complaints in a letter to congressional leaders this week. They accused several major agencies -- the Justice Department, the Peace Corps and the chemical safety board -- of imposing "serious limitations on access to records."

The inspectors general are now appealing to Congress to help them do their jobs uncovering waste, fraud, and mismanagement.

"Agency actions that limit, condition, or delay access thus have profoundly negative consequences for our work: they make us less effective, encourage other agencies to take similar actions in the future, and erode the morale of the dedicated professionals that make up our staffs," they wrote.

The letter to the chairmen and ranking members of relevant oversight committees in the House and Senate claimed agencies are withholding information by calling it "privileged."

In the letter, they said this interpretation poses "potentially serious challenges to the authority of every Inspector General and our ability to conduct our work thoroughly, independently, and in a timely manner."

House Oversight Committee Chairman Darrell Issa, R-Calif., calls that extremely troubling.

"If there is anyone who should have transparency, it should be the watchdogs inside the government working for the president," Issa told Fox News in an interview.

The letter offered specific examples of investigators having trouble getting what they need.

In the case of the Peace Corps, it withheld records of sexual assaults against its volunteers. A Peace Corps spokeswoman told Fox News, "We are committed to working with the inspector general to ensure rigorous oversight while protecting the confidentiality and privacy of volunteers who are sexually assaulted."

At the Justice Department, the letter said officials withheld records for three reviews until they found the reviews were helpful to department leadership.

Justice spokesman Brian Fallon said everything sought was provided and "because the documents at issue included grand jury material, credit reports, and other information whose dissemination is restricted by law, it was necessary to identify exceptions to the laws to accommodate the inspector general's request."

The watchdogs also claimed the EPA's inspector general had problems getting documents from the Chemical Safety and Hazard Investigation Board for a separate investigation.

Issa said that since most IG activities are not public until they are completed, "some of the best examples of obstruction probably are the ones the IGs don't want to say in a public format."

The letter notes a 1978 law ensures inspectors general have "complete, unfiltered, and timely access to all information and materials ... without unreasonable administrative burdens."

Issa called the letter unprecedented. "I've never seen a letter like this, and my folks have checked -- there has never been a letter even with a dozen IGs complaining."

He added, "This is the majority of all inspectors general saying not just in the examples they gave, but government wide, they see a pattern that is making them unable to do their job."

Sen. Charles Grassley, R-Iowa, the top Republican on the Senate Judiciary Committee, has long voiced concerns about impediments faced by the IGs, and used the letter to hammer the administration on that point. "This is an administration that pledged to be the most transparent in history. Yet, these nonpartisan, independent agency watchdogs say they are getting stonewalled," he said.

Issa said he's planning to hold hearings on this issue when Congress, which currently is on recess, returns in September.