US immigration agents began deploying at more ‌than a dozen US airports on Monday to aid security screening, as staffing absences by unpaid airport security officers have caused massive delays.

The Homeland Security Department confirmed it had begun deploying hundreds of Immigration and Customs ​Enforcement agents to assist in airport security at airports facing significant staffing issues.

ICE ​and Homeland Security Investigations officers were being deployed to around 14 airports, including Atlanta, JFK ⁠in New York, New York LaGuardia, Newark, New Orleans, Cleveland, Pittsburgh, Newark, Phoenix, and Fort Myers, according to ​officials and social media posts.

Separately, Atlanta Hartsfield-Jackson — the busiest US airport — told passengers to arrive at ​least four hours early on Monday for flights.

Social media posts showed ICE agents standing near Transportation Security Administration officers who were checking IDs.

For now, ICE personnel will not be deployed in areas behind airport ​security checkpoints because they lack the specific clearance needed, sources told Reuters.

On Saturday, absences ​among the approximately 50,000 TSA security staff reached 11.5%, their highest since a partial government shutdown began ‌five weeks ⁠ago.

At airports in Houston, New York and Atlanta, more than one-third of TSA staff were calling in sick or otherwise absent, DHS said, as the shutdown left tens of thousands working without pay while congressional Democrats and Republicans argue over the DHS budget.

Atlanta Mayor ​Andrew Dickens said federal ​officials had indicated ⁠that the ICE deployment would support TSA in crowd control and managing security lines in domestic terminals, and is “not intended to conduct immigration ​enforcement activities”.

Announcing ICE deployment at airports on Saturday, President Donald ​Trump said ⁠agents’ activities would include “the immediate arrest of all Illegal Immigrants who have come into our Country”.

Democrats have held up funding for DHS while demanding a change in rules governing its immigration ⁠operations, after ​ICE agents shot and killed U.S. citizens and , sparking public outrage.

More than 400 TSA agents have resigned since the start of the latest partial government shutdown ​on February 14.