Washington DC - President Donald Trump on Saturday threatened to use Immigration and Customs Enforcement agents to provide security at airports, amid a lingering budget standoff that has left regular security personnel going unpaid.

Trump wrote on Truth Social that if Democrats did not immediately sign a funding agreement, "I will move our brilliant and patriotic ICE Agents to the Airports where they will do Security like no one has ever seen before."

The post came hours after tech tycoon Elon Musk offered to cover the salaries of US airport security personnel who have been working without pay since mid-February.

The lapse in funding is forcing thousands of Transportation Security Administration staff – workers who screen airport passengers, baggage, and cargo – to work without pay as spring travel picks up.

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The agency, which operates under the authority of the Department of Homeland Security, comprises about 65,000 employees, according to its website. Various estimates put its annual payroll at somewhere between $2.5 billion and $3 billion.

"I would like to offer to pay the salaries of TSA personnel during this funding impasse that is negatively affecting the lives of so many Americans at airports throughout the country," Musk posted on X.

Democrats in Congress oppose any new funding for DHS until changes are implemented to how ICE conducts immigration operations.

Democrats have demanded curtailed patrols, a ban on face masks, and a requirement that ICE agents obtain a judicial warrant before entering private property.

While ICE is part of the Department of Homeland Security, it has been able to maintain operations using funds approved by Congress last year. But the TSA workforce is showing signs of stress.

More than 300 TSA employees have quit since the shutdown began on February 14, according to the DHS, while US media reported unscheduled absences had more than doubled.

Some officers are taking on second jobs or relying on donations, union officials say, while several major airports are collecting gift cards and stocking food pantries for TSA staff struggling without pay.

Airports in several cities have warned passengers to arrive hours earlier than usual because of long security lines.

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"Numerous employees have reported to me that their bank accounts are at zero or negative," Johnny Jones, a Dallas-based official in government workers' union AFGE, told USA Today.

"No funds for daycare, no funds for food. They just want to know why the hell they can't get paid when we have money to shoot missiles into other countries."

After the killing of two American citizens protesting aggressive ICE raids in Minneapolis in January, Trump fired Homeland Security chief Kristi Noem, but the immigration agency remains deeply unpopular for many Americans.

In his post Saturday, Trump took a dig at the Democrat-run state where Minneapolis is located, saying that if deployed to airports, ICE agents would immediately arrest illegal immigrants who have "totally destroyed...the once Great State of Minnesota."