In what is already fast becoming the latest flashpoint in the debate over allowing millions more illegal immigrants to remain in the United States legally, a government watchdog agency found that U.S. immigration officials released more than 600 undocumented immigrants in 2013 when faced with across-the-board budget cuts.

The Homeland Security Department’s inspector general released a report late Tuesday that found that Immigration and Customs Enforcement made the decision to release the criminals in order to cover the expected cuts from the sequester and budget impasse on Capitol Hill and free up detention bed space. The report said the ICE officials tried to differentiate between criminals who posed an ongoing threat from those convicted of lighter crimes, and released only those they believed weren’t a danger to society.

The release of the immigrants with criminal convictions breaks a federal law that requires them to be detained.

The IG report found that senior ICE officials did not have the permission of DHS leadership or the White House and did not inform them of their plans to release the criminals.

Reacting to the report, Arizona GOP Sens. John McCain and Jeff Flake, along with Sen. Tom Coburn, R-Okla., are pressing the Department of Homeland Security for more information on how it manages the release of illegal immigrants.

In a letter to DHS Secretary Jeh Johnson, McCain and Flake cited a series of disturbing crimes committed in recent weeks and months by illegal immigrants who had been deported multiple times, including the first-degree murder of an off-duty U.S. Border Patrol agent in Texas and the alleged molestation of a nine-year old girl.

“These disturbing cases raise serious concerns about the effectiveness of our current immigration system and the safety of our citizens who live near the border,” they wrote.

“We cannot secure our border communities if DHS fails to coordinate the activities of its component agencies or act on intelligence indicating new risks.”