US President Donald Trump warned Minneapolis Mayor Jacob Frey on Wednesday that he was "playing with fire", after the mayor said the city would not enforce immigration laws.

"Could somebody in his inner sanctum please explain that this statement is a very serious violation of the Law, and that he is PLAYING WITH FIRE!" Trump posted on social media.

In response, Frey wrote, "The job of our police is to keep people safe, not enforce fed immigration laws".

The exchange came despite the president saying his administration would "de-escalate a bit" in the city.

Reuters reported that tensions remained high in Minneapolis, where observers and activists say immigration raids had not slackened but appeared to be more targeted, despite Trump having said after a second fatal shooting that the administration would reduce the number of border patrol officers.

The city has been roiled by unrest, including confrontations between protesters and immigration agents, resulting in two US citizens being shot dead by federal agents.

Alex Pretti, 37, an ICU nurse at a VA hospital, was shot and killed by agents on Saturday during a Department of Homeland Security raid. DHS officials initially said that Pretti was brandishing a gun, though videos taken at the scene suggested otherwise.

Saturday's shooting raised tensions further between state and federal officials, which had already been at odds with the US administration over the shooting of Renee Good in Minneapolis on Jan 7.

After the shooting of Good, the administration also claimed that she had intended to harm federal agents, though cellphone footage of the incident raised questions about the federal government's description of the incident.

Two border patrol agents who fired their guns during Pretti's shooting have been placed on administrative leave, according to DHS spokesperson Tricia McLaughlin.

Frey said city police officers are overwhelmed. With both protesters and federal agents alike calling 911 for help, officers across the region have struggled to respond. Police and union officials say morale has plummeted as officers find themselves caught between powerful political forces beyond their control, The New York Times reported.

"Both sides dug their heels in, and here we are in the middle of it," said Mark Ross, president of the Saint Paul Police Federation, the capital city's police union. "They are playing political football and we are the ones getting kicked around."

Demonstrators have also pleaded for more protection from the Minneapolis Police Department, The New York Times reported, though the department's 600 officers are outnumbered by the 3,000 federal officers sent by the Trump administration.

Trump and Minnesota Governor Tim Walz talked on Monday, and "agreed on the need for an ongoing dialogue".

Border czar Tom Homan also met with Walz, looking for ways to lower the temperature between federal and state authorities. Homan will take over operations in the state from Gregory Bovino, the border patrol official whose aggressive tactics drew widespread criticism, Reuters reported.

A Trump administration official said the change would mark a shift to more traditional targeted operations rather than the broad street sweeps Bovino has led in multiple cities. Yet it remained unclear how much would change in a city where federal agents have regularly clashed with protesters, Reuters reported.

The state is the latest battleground between local police, residents and federal law enforcement. Similar tensions surfaced in Chicago last year, as well as over the summer in Los Angeles, which was the first city to see a surge of immigration enforcement. But the scale of the Trump administration's operation in Minnesota, the concentration of forces in a city the size of Minneapolis, the pushback from local leaders and the resistance from residents have all raised the stakes, The New York Times reported.

Trump has threatened to cut funding for states that include so-called sanctuary jurisdictions, which limit how much cooperation they give federal immigration authorities, Reuters reported.

shiguang@chinadailyusa.com