The Trump administration's battle with so-called sanctuary cities escalated Wednesday when the Department of Justice, under the guidance of Attorney General Jeff Sessions, asked for records from 20 cities and countries, including the country's three largest, as well as California, Illinois and Oregon.

The documents would reveal whether law enforcement agencies in these jurisdictions are illegally withholding information from US immigration authorities in violation of federal law, Reuters reported. Most sanctuary cities have passed local laws meant to stop municipal law enforcement from sharing an arrestee's immigration status with ICE.

“If these jurisdictions fail to respond to our request, fail to respond completely or fail to respond in a timely manner, we will exercise our lawful authorities and issue subpoenas for the information,” said a senior Justice Department official, briefing reporters on condition of anonymity.

Trump's battle with sanctuary cities has been raging for nearly his entire tenure in office, beginning just days after his inauguration when he signed an executive order to bar federal funding to cities that failed to cooperate with immigration authorities. This order was swiftly blocked by a federal appeals court, like so many of Trump's other immigration-related policies. As a candidate, Trump promised to deport all of the roughly 11 million undocumented immigrants living in the US.

New York, Los Angeles and Chicago are each being targeted, as are Denver, San Francisco, the Washington state county that includes Seattle, Louisville, Sacramento, Albany, West Palm Beach and others, according to Reuters.

Some cities, including Philadelphia, didn't make the list because of pending litigation.

Last March, Attorney General Jeff Sessions made a surprise appearance at then-White House Press Secretary Sean Spicer's press briefing to announce that the DOJ would take steps to require sanctuary cities to comply with federal immigration laws, or see federal public-safety grants withheld. The DO would even try to claw back past DOJ awards, Sessions said. But the agency was quickly blocked by a flurry of lawsuits by Chicago, San Francisco and Philadelphia.

The judge overseeing the Chicago case issued a nationwide injunction barring the DOJ from withholding what is known as Byrne JAG grant money on the constitutional grounds. These funds are typically used to help local police improve crime-fighting techniques, buy equipment and assist crime victims. The DOJ is appealing this ruling.

According to Reuters, supporters of the sanctuary movement say enlisting local law enforcement officers’ support in rounding up immigrants for deportation undermines trust in local police.

Some cities have said they will honor requests by immigration authorities when accompanied by a criminal warrant.