The crisis at the border is putting U.S. security “at grave risk” because the U.S. Customs and Border Protection has been forced to divert 40% of its officers to holding facilities to care and process illegal crossers, according to an government group.

The report from the Homeland Security Advisory Council said that the crisis has forced Border Patrol to take 6,643 of its 16,688 officers off “the line” and to help with the surge of tens of thousands of illegal immigrants.