Federal government agencies spend $1.5 billion annually on public relations, according to a new report from the Government Accountability Office, a finding that is likely to displease fiscally conservative members of Congress.

The watchdog agency reported that agencies spend about $1 billion annually on public relations and advertising, and another $500 million in salary for roughly 5,000 federal PR employees.

Senate Budget Committee Chairman Mike Enzi, R-Wyo., requested the report in February after failing to get information about PR spending from the Obama administration. At the time, Enzi warned that some PR spending could run afoul of regulations against propaganda and that the government didn't have the finances to spend money on advertising.

"With increasing pressures on limited federal resources, it is crucial to know how much is spent across the federal government on public relations activities and which federal agencies are spending the most," Enzi said of Wednesday's report.

The biggest-spending agency by far, according to the report, is the Department of Defense, which has spent an average of just under $630 million a year on PR in the past decade. It has more than 2,000 PR employees.

Health and Human Services was the only other agency to average over $100 million annually in PR spending. Homeland Security, Commerce and Transportation rounded out the top five spenders.