Tom Homan, the White House border czar, confirmed on Sunday that Immigration and Customs Enforcement agents would be deployed to U.S. airports on Monday, casting the operation largely as an effort to ease long lines that have caused frustration among travelers during one of the busiest travel seasons.

ICE personnel, including agents from Homeland Security Investigations, are planning to be at 14 airports, according to a document obtained by The New York Times. The airports span the country, including Kennedy and LaGuardia in New York, Newark, Philadelphia, Chicago, Atlanta, New Orleans, Houston and Phoenix.

The agents are expected to conduct tasks to free up Transportation Security Administration agents to handle processing travelers, according to an official from the Homeland Security Department, who spoke on the condition of anonymity because he was not authorized to discuss the location of ICE agents.

President Trump announced the measure on Saturday, first as a threat aimed at pressuring congressional Democrats to agree to a deal to fund the Homeland Security Department, which includes the T.S.A., and then as an aggressive operation. He said on social media that agents would “do security like no one has ever seen before,” which would include “the immediate arrest of all illegal immigrants who have come into our Country.”

In an interview on CNN’s “State of the Union” on Sunday, Mr. Homan said that his agency was drawing up plans for deployment and stressed that ICE agents would help support security officials whose ranks have thinned as thousands have gone without pay amid a partial government shutdown.

“It’s a work in progress, but we will be at airports tomorrow, helping T.S.A. move those lines along,” Mr. Homan said.