Officials at Immigration and Customs Enforcement, or ICE, said the immigration roundups that people were seeing did not represent an increased tempo. The agency has about 100 fugitive teams constantly working to bring in those wanted on a variety of immigration offenses, and these teams have been just as active as they were during the Obama administration, officials said. In 2012, the most active year for deportations during Mr. Obama’s presidency, 409,849 people were deported.

In a news release Friday, ICE described as routine a five-day “targeted enforcement action” in which roughly 160 people were arrested in six counties around Los Angeles. Of those, 150 had criminal histories, some of them serious.

Some had already been ordered deported before Mr. Trump took office; according to ICE statistics, there are 960,000 people with deportation orders who are not in custody.

“The rash of recent reports about purported ICE checkpoints and random sweeps are false, dangerous and irresponsible,” ICE said in a statement Friday. “These reports create panic and put communities and law enforcement personnel in unnecessary danger.”

Officials noted, however, that they did expect the numbers and deportations to increase in line with the president’s order. In Los Angeles, for example, the county sheriff’s department was told by ICE that it planned to issue “detainers” for every illegal immigrant charged with a crime, no matter how serious, according to Capt. Elier Morejon.

Jonathan Blazer, the advocacy and policy counsel for the American Civil Liberties Union, said the group had been wary of deportation tactics for years.