D.C. Police Chief Peter Newsham, left, and Mayor Muriel Bowser. (Michael S. Williamson/The Washington Post)

The D.C. police said Friday on Twitter that the department will not enforce civil immigration laws, a statement that appeared to suggest opposition, at least in principle, to federal plans to begin rounding up migrant families that have received deportation orders.

It is unclear whether the D.C. police policy will have any effect on the federal effort.

The D.C. police have said in the past that they have long-standing policies to “ensure officers are not involved in the enforcement of federal immigration laws.”

The police statement on Twitter appeared to reflect a message released Friday by D.C. Mayor Muriel E. Bowser (D) that criticized what she said were deportation threats made by President Trump.

Bowser said the president “should understand that not only are these threats cruel and antithetical to our American values, they are actually making our communities less safe by sending more residents into hiding, cut off from resources, support, and opportunity.”

The statements by Bowser and the police came amid news reports that the president has directed U.S. Immigration and Customs Enforcement agents to conduct a mass roundup of migrant families that have received deportation orders.

According to the reports, which are based on information from U.S. officials with knowledge of the plans, the federal operation is likely to begin with early-morning raids in major cities as soon as Sunday.

It was not clear whether Washington would be among the cities.

In Los Angeles, the police said they were not going to participate or aid in enforcement actions they said were to start Sunday and target people who have been issued final deportation orders.