Department of Homeland Security Secretary Jeh Johnson urged lawmakers Sunday to reach a deal to fully fund his agency, saying a shutdown would jeopardize national security.

DHS is currently funded through Feb. 27, as Congress continues to fight over a funding bill for the agency. Republicans are seeking to use a new spending bill to punish President Obama for his executive actions on immigration. Democrats are blocking GOP efforts to roll back the president’s actions.

During an interview on CNN’s “State of the Union," Johnson called for funding that is “separate and apart” from debate over immigration policies. A shutdown of the agency would result in the furloughing of 30,000 employees, he said.

"If people in Congress want to have that debate about immigration reform, let's have that debate. But don't tie that to public safety and homeland security for the American people," he said.

Johnson said temporary measures to fund his department, such as continuing resolutions, are restricting new initiatives, including border security efforts, grants to state and local law enforcement and new Secret Service agents for the upcoming presidential election cycle.