With the indictment last week of two Iraqi refugees who allegedly conspired with ISIS, a number of lawmakers are now warning that poor screening methods and an administration plan to boost immigration will endanger national security.

Recent efforts by Congress to investigate the immigration histories of at least 113 foreign-born individuals snagged on terror charges since 2014 have been blocked by the Obama administration. There are at least 1,000 open investigations into ISIS members residing in the United States, sources said.

New cases of legal immigrants participating in alleged terrorist plots are cropping up on a near daily basis, according to Sen. Ted Cruz (R., Texas), who has been spearheading an effort to investigate how these individuals are passing through U.S. security screenings.

“Almost every day there is a new case that documents the relentless attacks being waged against our nation,” said Cruz. “We have militants who have infiltrated waves of refugees to come to American and plot attacks. We have Americans who have travelled abroad to train returning to wage jihad here. We have home-grown terrorists who are receiving instruction online to hatch attacks.”