President Donald Trump said Monday that he may send “more federal law enforcement” to Philadelphia and other major cities even though protests here have remained peaceful in recent weeks.

This announcement seemed to take local officials by surprise, with both Mayor Jim Kenney and Police Commissioner Danielle Outlaw saying they did not receive any advance notice of the president’s comments. It’s unclear if Trump will send federal officers to Philadelphia, and if they are, which agencies would be involved or when it would happen.

Kenney said he would oppose such a move.

”The president’s threat is wrong on many levels. To send federal agents to police U.S. cities that have not requested such aid can only impede the work of local governments and exacerbate already heightened tensions in these cities,” Kenney said in a statement. “And to target cities that are led by Democratic mayors is clearly a politicization of federal resources that should outrage all taxpayers.”

Trump lauded the use of force by local and federal officers during protests in Portland, Ore., that have followed the Minneapolis police killing of George Floyd.

“In Portland, they’ve done a fantastic job,” Trump said Monday during a meeting on the GOP’s coronavirus relief bill. Trump also mentioned New York, Chicago, Detroit, Baltimore, and Oakland, Calif., as cities where he would consider sending “more federal law enforcement.” The U.S. Department of Homeland Security is planning to send about 150 federal agents to Chicago this week, the Chicago Tribune reported Monday.

While the Portland protests have led to some violence, like a fire in the police union headquarters and the federal courthouse, most have remained peaceful. And those protesters appear more determined after seeing aggressive responses by federal officers, like using tear gas and pulling demonstrators into unmarked vans, according to local media, accounts from protesters, and videos circulated on social media.

“We are in a fight to save our democracy,” Reggie Shuford, executive director of the ACLU of Pennsylvania, said in a statement. “If federal authorities come to Philadelphia with the same unjustified and unconstitutional tactics that they’re using in Portland, they can expect a strong response from us and from our partners who are pushing America to reckon with its history of brutalizing Black people.”

Oregon officials have said the federal officers’ presence in the state’s largest city is not welcome. The city has seen almost two months of nightly protests, and the federal officers are making tensions worse, they said.

“Their presence is neither wanted nor is it helpful, and we’re asking them to leave,” Portland Mayor Ted Wheeler said, according to the Washington Post. “In fact, we’re demanding that they leave.”

Jennifer Crandall, a spokesperson for William M. McSwain, U.S. attorney for the Eastern District of Pennsylvania, said her office had no comment about Trump’s remarks. Pat Trainor, a spokesperson for the Philadelphia Drug Enforcement Administration, said he was “unaware of the DEA or any other federal agencies being mobilized at this time.” District Attorney Larry Krasner compared Trump’s threat to fascism.

“My dad volunteered and served in World War II to fight fascism, like most of my uncles, so we would not have an American president brutalizing and kidnapping Americans for exercising their constitutional rights and trying to make America a better place, which is what patriots do,” Krasner said. “Anyone, including federal law enforcement, who unlawfully assaults and kidnaps people will face criminal charges from my office.”

Oregon Attorney General Ellen Rosenblum has sued federal officials, alleging that unidentified federal agents have grabbed people off Portland streets “without warning or explanation, without a warrant, and without providing any way to determine who is directing this action.”

Officers across the country have responded with force to people demonstrating against racism and police brutality. In Philadelphia, officers teargassed and assaulted peaceful protesters and deployed military-style vehicles in a residential neighborhood. The city has since apologized for some of its tactics.

More than 140 Philadelphia protesters and residents have sued the city, saying the June 1 teargassing of a crowd of demonstrators on I-676 and the police use of rubber bullets, pepper spray, and tear gas along 52nd Street in West Philadelphia the day before violated their constitutional rights to free expression and freedom from excessive force.

Natasha Merle, a senior counsel with the NAACP Legal Defense and Educational Fund, which is representing 13 plaintiffs in one of the federal suits about the use of force along 52nd, said she has “serious concerns” about the recent deployment of federal troops during protests.

“If what is happening in Portland expands to Chicago, Philadelphia, other cities, we would think that is an unconstitutional overreach by the federal government,” Merle said. “We’ve already brought our lawsuit on behalf of Black communities in Philadelphia already being traumatized. Federal officers deployed in Philadelphia would only continue that trauma.”

Staff writer Chris Palmer contributed to this article.