Members of Congress who criticize how the Department of Homeland Security does its job should change immigration laws if they don't want to see them enforced, Homeland Security Secretary Kirstjen Nielsen.

"I really fear for our democracy when the body who creates the law is telling the body who enforces the law, just don't enforce the law," Nielsen told Fox News' "Fox and Friends."

"The men and women at the Department of Homeland Security have sworn an oath to protect communities to secure the homeland and to enforce the law that Congress passed.”

Nielson's interview aired just hours before the Senate was expected to pass a resolution rejecting President Donald Trump's emergency declaration for the border, and as the DHS has been criticized for implementing many of the president's policies at the border.

She said Trump was within his constitutional authority to declare an emergency, and that many members of Congress are criticizing Customs and Border Patrol for enforcing policies such as on family separations that have been in effect for decades but are "suddenly now political and partisan."

Meanwhile, apprehensions at the border are going up, and Nielsen said that is happening because criminals are finding ways to take advantage of loopholes.

Then, Congress also fails to act, she said.

"This is not a partisan issue," said Nielsen. "It is not partisan to want to protect communities and not partisan to want to secure our border or homeland. And, yet, in this environment, Congress refuses to act.