WASHINGTON (AP) -- Independent watchdogs from dozens of federal agencies are decrying what they say are Obama administration efforts to delay or stall their investigations.

Inspectors’ general complained of a lack of access from their agencies in a letter sent Tuesday to members of Congress.

It cites specific instances in which inspectors general from the Peace Corps, the Environmental Protection Agency and the Department of Justice said that they had been denied timely access to documents and other information while doing investigations.

The inspectors general say refusing or delaying a request for documents leads to "incomplete, inaccurate, or significantly delayed findings or recommendations."

Sen. Chuck Grassley, the top Republican on the Senate Judiciary Committee, asked in a statement how watchdogs are "supposed to be able to do their jobs without agency cooperation."