The acting head of the Cybersecurity and Infrastructure Security Agency on Wednesday painted a bleak picture of how the organization would be impacted by even a temporary interruption in funding to the Homeland Security Department.

A shutdown would “degrade our capacity to provide timely and actionable guidance to help partners defend their networks,” acting CISA Director Madhu Gottumukkala told the House Appropriations Homeland Security subcommittee.

He said operations would become “strained” and core missions, such as digital response, would be curtailed as well as force “over a third of our frontline security experts and threat hunters to work without pay, even when nation-states intensify efforts to exploit the systems that Americans rely on.”

“I want to be clear: when the government shuts down, cyber threats do not,” Gottumukkala, who testified alongside the heads of four other DHS elements, told the panel.

The warning comes as a shutdown of DHS becomes increasingly likely. 

Lawmakers are racing against the clock to secure a deal that would fund DHS and enact changes to how immigration officers remove unauthorized immigrants. A short-term funding patch for DHS expires on Friday and Democrats have signaled a willingness to allow a partial shutdown unless the administration agrees to make changes at ICE and Border Patrol following shootings in Minneapolis.

In addition to cutting off paychecks for around 900 CISA staffers, a shutdown would impede the agency work updating a long-awaited cyber incident reporting rule, according to Gottumukkala.

CISA’s activities would be “strictly limited to those that are essential to protecting life and property … We only look at anything that is an immediate need and an imminent threat. We will not be able to do proactive vulnerability scanning,” he said.

“Our adversaries are always working, 24/7. We will be on the defensive, reactive, as opposed to being proactive and strategic in terms of how we will be able to combat those adversaries.”

Gottumukkala said CISA has transferred about 70 employees to other DHS components using reassignment authorities and has taken in more than 30 employees from other components. He noted a “handful” of personnel have been moved to ICE. CISA has lost about one-third of its staff since the start of the second Trump administration.

Panel Republicans stressed that a DHS shutdown would not stop the work of the agencies Democrats are most worried about. 

“Removal operations will continue. Wall construction will continue,” Rep. Mark Amodei (R-NV), the subcommittee chair said.

Rep. Rosa DeLauro (CT), the top Democrat on the full Appropriations Committee, on Wednesday introduced legislation that would fund all DHS components except for ICE and CBP.

"If Republican leadership blocks this legislation from moving forward, they are responsible for any shuttered agencies, furloughed workers, missed paychecks, or reduced services," she said.