Arizona’s two Republican senators on Tuesday demanded that the Department of Homeland Security explain what steps it will take to ensure it doesn’t release illegal immigrants with criminal convictions.

Sens. John McCain and Jeff Flake were reacting to a report from the DHS Office of Inspector General, which said the 2013 release of more than 2,000 illegal immigrants by Immigration and Customs Enforcement was done without guidance from DHS or other officials.

Sens. Jeff Flake (R-Ariz.) and John McCain (R-Ariz.) are demanding that DHS explain its policies for the release of illegal immigrants. Chip Somodevilla/Getty Images

The two senators noted that some immigrants have had to be re-arrested for other criminal convictions, including the murder of an off-duty border patrol agent, molesting a nine-year old girl, and the killing of a police officer.

“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.”

The senators asked DHS to explain what steps it will take to ensure there are no more unplanned releases of detainees. It also asked how many undocumented immigrants have been detained for trying to re-enter the U.S. after being deported.

Read McCain and Flake’s letter here: