WASHINGTON (AP) — The White House is warning Congress that funding to pay Department of Homeland Security personnel will "soon run out," sparking new threats of airport disruptions and national security concerns as the House slow-walks legislation to end what has been the longest-ever lapse in agency funding.

In a memo late Tuesday to lawmakers, the Office of Management and Budget said and other workers through executive actions will be exhausted by May. It called on the House to quickly approve the budget resolution senators approved in an all-night session last week that would pave the way for full funding for the department.

"DHS will soon run out of critical operating funds, placing essential personnel and operations at risk," the memo said.

The pressure from the Trump administration could help House Speaker Mike Johnson, whose narrow Republican majority has been stalled out, tangled in internal party disputes on a range of pending issues, including the Homeland Security funding. They have left the chamber at a virtual standstill.

The House was expected to vote as soon as Wednesday on the Senate budget resolution that is designed to unlock a multistep process to eventually fund the department. But by midday, House action again screeched to a halt. The administration has warned GOP lawmakers off making changes that could prolong passage.

"Restoring funding for the Department of Homeland Security (DHS) has never been more urgent, as demonstrated by recent events," the memo said, a nod to the situation over the weekend when a man armed with guns and knives tried to storm the annual White House correspondents' dinner that Trump, the vice president and top Cabinet officials were attending.

Homeland Security shutdown is longest ever

Homeland Security has been operating without regular funds for more than two months after Democrats refused to fund Immigration and Customs Enforcement and Border Patrol without changes to those operations after the deaths of Americans protesting Trump's deportation agenda.

READ MORE: What to know about Trump's executive order to pay TSA officers and its impact on airport security lines

While immigration enforcement workers have largely been paid through the flush of new cash — some $170 billion — that Congress approved as part of Trump's tax cuts bill last year, others, including TSA, have had to rely on Trump's intervention through executive action to ensure their paychecks.

But with salaries topping $1.6 billion every two weeks, DHS Secretary Markwayne Mullin said recently, those funds are drying up.

More than 1,000 TSA officers have quit since the shutdown began, according to Airlines for America, the U.S. airlines trade group that called Wednesday on Congress to fully fund the agency.

"The urgency to provide predictable and stable funding for TSA is growing stronger by the day," the group said in a statement. "Time and time again, our nation's aviation workers and customers have been the victim of Congress' failure to do their jobs."

Complicated budget strategy ahead

House and Senate Republicans have embarked on a go-it-alone strategy, attempting to approve funds for Immigration and Customs Enforcement and Border Patrol without Democrats. They want to provide $70 billion for those immigration operations for the remainder of Trump's term to ensure no further interruptions.

It's a cumbersome process, the same that was used last year to approve Trump's tax cuts bill, that will play out over several weeks.

The Senate launched the process last week, and is now waiting on the House to act. Once that budget resolution is approved, both the House and Senate are expected to draft the actual funding bill, a process that can take weeks.

In the meantime, Johnson is next expected to quickly turn this week to legislation that would fund the other parts of Homeland Security, including TSA, the Coast Guard and other agencies.

That bipartisan bill has support from Democrats and already passed the Senate a month ago, when Republicans reluctantly agreed to carve out the immigration-related funds that Democrats had opposed. But it has been stalled out in the House, as Republicans in that chamber disagreed with the Senate's approach.

Associated Press writer Rio Yamat in Las Vegas contributed to this report.