Oregon’s congressional delegation on Wednesday formally requested an investigation into the response by the Department of Homeland Security (DHS) and the Justice Department to the riots in Portland -- after DHS pledged not to back down.

In a letter, Sens. Jeff Merkley and Ron Wyden, D-Ore., along with Reps. Earl Blumenauer and Suzanne Bonamici, D-Ore., wrote to the agencies’ inspectors general requesting investigations into the federal presence in Portland in response to threats against monuments and federal property.

DHS CHIEF PROMISES 'WE WILL NOT RETREAT' FROM PORTLAND DESPITE CRITICISM, TELLS RIOTERS 'FIND ANOTHER LINE OF WORK'

“The American people deserve transparency and accountability,” the delegation wrote. “We live in a democratic republic, not an authoritarian police state. The repeated use of federal force against civilians warrants urgent investigation and raises serious questions about the directives behind this effort and misuse of force that has an apparently political motivation.”

The delegation cites instances such as a protester being hit in the head by a canister, reports of “unmarked” agents putting protesters into minivans (DHS has denied that officers were unidentified), and the use of tear gas and munitions against protesters.

DHS sent law enforcement to Portland earlier this month after weeks of rioting and over fears of attacks on monuments and federal property -- particularly the Hatfield Courthouse, which has repeatedly been attacked.

Officers have reportedly been attacked, doxed and injured by rioters, with DHS officials saying weapons including hammers, fireworks and fecal matter having been used against law enforcement.

US ATTORNEY CALLS FOR PROBE INTO FEDERAL CRACKDOWN ON PORTLAND RIOTS 

But Democratic politicians and other local officials have accused the government of escalating the situation, accusing them of heavy-handedness. Mayor Ted Wheeler has called on the agency to leave the city. The U.S. attorney for Oregon has also called for the DHS inspector general to investigate the agency’s response.

The congressional delegation on Wednesday requested the IG “provide a detailed explanation about: the chain of command that governs these tactical response teams; their training and safety protocols on use of crowd control tactics and weaponry; their directives to apprehend civilians in downtown Portland; their coordination with local law enforcement officials and elected representatives, if any; and the intent of these tactics, which appear to be motivated not by reducing tensions between the people of Portland and law enforcement agencies but instead by a desire to demonstrate unfettered power over the people of Oregon. “

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But as the controversy over the federal response continues, Acting DHS Secretary Chad Wolf said during a news conference Tuesday that DHS would not back down.

“If you are a violent rioter looking to inflict damage on federal property or law enforcement officers, you need to find another line of work,” Wolf said. “We will not retreat, we will continue to protect our facilities and our law enforcement officers.”