US Immigration and Customs Enforcement (ICE) agents will be sent to airports to help with increasingly long lines at security checkpoints, the Trump administration has said.

President Donald Trump posted on social media that ICE agents will go to airports on Monday, while border tsar Tom Homan told CNN that his team was working out the details of the plan.

The union that represents the Transportation Security Administration (TSA) officers criticised the move, saying staff deserve to be paid, not replaced by untrained, armed agents.

Travellers have faced hours-long airport security queues in recent days as the partial government shutdown affecting the Department of Homeland Security continues.

The DHS has gone without funding since mid-February, after Congress failed to reach an agreement - leaving normal airport security staff without pay.

Trump posted on Truth Social: On Monday, ICE will be going to airports to help our wonderful TSA Agents who have stayed on the job. Trump's comments came a day after he threatened to send ICE agents to airports if Democrats did not immediately agree to fund DHS.

I will move our brilliant and patriotic ICE Agents to the Airports where they will do Security like no one has ever seen before, Trump posted on Saturday. The ICE agents will not be directly involved in screening passengers, Homan told CNN's State of the Union. Instead, they will be used to free up TSA agents to conduct the screenings they are trained to do, he said.

Homan suggested ICE agents would cover entry and exit points so that relieves that TSA officer to go to screening and to reduce those lines. The border tsar added that he is still working with the TSA and ICE to iron out the details, including how many agents would be involved.

Speaking to ABC News' This Week, Transport Secretary Sean Duffy suggested a wider role for ICE, indicating their experience with security machines used at southern border."Additionally, a DHS spokesperson said that the president is using all available tools to assist American travelers amidst the ongoing challenges related to air travel security.

Despite these assurances, House Minority Leader Hakeem Jeffries expressed concern about the deployment, referring to it as the last thing that the American people need and underscoring the untrained nature of the individuals potentially replacing trained TSA officers.

As the deadlock over funding continues, TSA agents have gone unpaid for more than a month, causing a rise in absenteeism and staff shortages, which may complicate the ongoing logistical scenarios at America’s airports.