The mayor of Portland in Oregon has renewed his call for federal officers to leave the US city, accusing them of abusive tactics against protesters.
"They are sharply escalating the situation," Mayor Ted Wheeler told CNN on Sunday.
There have been nightly protests against police brutality in the city since the death of George Floyd, an unarmed black man, in Minnesota in May.
The federal government has said it is trying to restore order in Portland.
Speaking to CNN on Sunday, Mayor Wheeler said there were "dozens if not hundreds of federal troops" in the city, adding: "Their presence here is actually leading to more violence and more vandalism.
"They're not wanted here. We haven't asked them here. In fact, we want them to leave," he said.
His comments echoed those of Oregon Governor Kate Brown, who described the presence of federal officers in the city as "purely political theatre" from President Donald Trump's administration.
Ms Brown told MSNBC that she had asked the federal government on Tuesday to remove the officers, saying: "You are escalating an already challenging situation."
Their comments came after Oregon's attorney general filed a lawsuit against the federal government, accusing it of unlawfully detaining protesters.
In the lawsuit, Ellen Rosenblum requested a restraining order to stop agents from the Department of Homeland Security, US Marshals Service, US Customs and Border Protection and the Federal Protection Service from making any more arrests in the city.
"These tactics must stop," Ms Rosenblum said in a statement.
The lawsuit said the actions of federal officers violated protesters' ability to exercise their constitutional First Amendment right to assembly and, by seizing and detaining people without a warrant, also breached the Fourth and Fifth Amendment right to due process.
The officers, a new Department of Homeland Security unit made up of people from the US Marshals Service and Customs and Border Protection, have been deployed under an executive order protecting statues, signed by Mr Trump last month.
The executive order, which says anyone who damages a public statue must be prosecuted to the "fullest extent of the law", allows federal officers to be deployed without the permission of the state.
Meanwhile on Sunday, Democrats in the House of Representatives called for watchdogs belonging to the departments of justice and homeland security to investigate whether the two bodies had "abused emergency authorities to justify the use of force" against protesters.
The letter, which was signed by the heads of three house committees, specifically mentioned the reports from Portland as well as the dispersal of Lafayette Square in Washington DC during protests in June.
"This is a matter of utmost urgency," they wrote. "Citizens are concerned that the Administration has deployed a secret police force, not to investigate crimes, but to intimidate individuals it views as political adversaries, and that the use of these tactics will proliferate throughout the country."
What's happening in Portland?
Federal agents, deployed by President Trump, have fired tear gas into crowds of demonstrators. Homeland Security Secretary Chad Wolf previously called the protesters a "violent mob".
Late on Saturday, protesters were seen dismantling a fence around the federal courthouse, hours after it was put up.
The prosecutor's office in Oregon said on Twitter that the fence aimed to "de-escalate tensions" between protesters and law enforcement officials and asked people to leave it alone.
Officers declared a riot outside the Portland Police Association building. It was set on fire.
The last week has seen a violent escalation between protesters and federal agents, deployed two weeks ago by Mr Trump to quell civil unrest.
A report from Oregon Public Broadcasting (OPB) this week contained detailed accounts of witnesses who had seen federal law enforcement officers dressed in camouflage emerge from unmarked vehicles, grab protesters without explanation, and drive off.
These federal officers (?) just rushed up and arrested someone for no reason pic.twitter.com/xcFVuoMZmN
— Matcha chai (@matcha_chai) July 15, 2020
Video checked by the broadcaster shows a protester, Mark Pettibone, describe how on 15 July he was "basically tossed" into a van containing people in body armour.
Mr Pettibone said he was taken to a holding cell in a federal courthouse, where he was read his arrest rights. After declining to answer questions, he was released without any citation or arrest record.
According to OPB, federal officers have charged at least 13 people with crimes.
What has the Trump administration said?
In a tweet on Sunday, President Trump defended the actions of the federal government.
"We are trying to help Portland, not hurt it. Their leadership has, for months, lost control of the anarchists and agitators," he said.
Earlier in the week, the president said officers in the city had done a "great job".
"Portland was totally out of control, and they went in, and I guess we have many people right now in jail," he said on Monday. "We very much quelled it."
Chad Wolf arrived in the city on Thursday and defended the agents against the assembled "anarchists".
He blamed state and city authorities for failing to "restore order", saying the "city of Portland has been under siege for 47 straight days".