WASHINGTON -- US President Donald Trump on Saturday threatened to deploy Immigration and Customs Enforcement (ICE) agents to provide security at airports amid an ongoing shutdown of the Department of Homeland Security (DHS), which has dragged on for more than a month and left regular security personnel going unpaid.

Trump wrote on Truth Social that if Democrats did not "immediately sign an 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 US Senate on Friday failed to advance a House-passed bill to fund the DHS due to bipartisan disagreement over immigration enforcement.

About 50,000 Transportation Security Administration (TSA) officers have been working without pay since Feb 14, when the US Congress let funding for the DHS, which oversees the TSA, expire over a disagreement on immigration enforcement. Major US airports are seeing long lines at security checkpoints, with security wait time exceeding three hours in some cases. Hardest-hit airports include those in Houston, Atlanta and New Orleans.

Over the last five weeks, negotiations between the two parties on immigration enforcement have shown little progress. Republicans have pushed to fund DHS, while Democrats have sought standalone funding for agencies like TSA that would exclude immigration operations.