House Democrats next month will get their first chance to grill Homeland Security Secretary Kirstjen Nielsen about President Trump’s immigration policy, which they say has resulted in the imprisonment of children in the U.S illegally.

“Secretary Nielsen has agreed to come before the Committee on Homeland Security to testify on March 6th. We are giving the Secretary ample time to prepare for this appearance. She should be ready to defend the Administration’s border security actions and its plans to improve its border security agenda going forward,” House Homeland Security Chairman Bennie Thompson said in a statement Monday.