Demands from the White House for a drastic increase in arrests of people who have entered the country illegally have pushed immigration officials into overdrive to fulfill President Trump’s pledge of mass deportations.

Immigrations and Customs Enforcement is carrying out workplace raids across the country like the one in the garment district of Los Angeles last week that kicked off protests and a vast federal response. The agency is staggering shifts so agents are available seven days a week to try to meet arrest goals and asking criminal investigators who usually focus on issues like human trafficking to help identify targets. It is also asking the public to call in tips to report illegal immigration.

ICE’s work is being aided by a new mapping app that locates people with deportation orders who can be swiftly expelled, drawn from data housed in agencies across the government, according to documents obtained by The New York Times.

“I said it from Day 1, if you’re in the country illegally, you’re not off the table,” Thomas D. Homan, Mr. Trump’s border czar, said in an interview. “So, we’re opening that aperture up.”

Stephen Miller, the White House deputy chief of staff, has been deeply engaged in the effort behind the scenes, meeting with top ICE officials in recent weeks and scrutinizing the numbers, according to people familiar with his involvement.

The intense pressure by top administration officials creates an atmosphere that elevates the potential for mistakes at a time when officers and agents are being pushed to make consequential decisions, former officials said.