Sen. Tom Cotton, R-Ark., placed holds on all Department of Justice nominees after DOJ failed to respond to his demand for answers about its lack of assistance to U.S. Marshals being sued over their defense of the Portland federal courthouse in 2020.

Eight Biden administration nominees are being held up by Cotton's action, including four U.S. attorney nominations awaiting votes on the Senate floor, two U.S. attorneys awaiting votes in Judiciary Committee and two U.S. Marshals awaiting votes in committee.

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Sen. Tom Cotton (Tasos Katopodis/Pool via REUTERS)

PORTLAND STRUGGLES TO REHIRE POLICE AFTER DEFUNDING AND RIOTS

The move comes after Cotton penned a letter to Attorney General Merrick Garland expressing concern about the DOJ's lack of legal assistance for U.S. Marshals facing lawsuits over their role defending the Portland federal courthouse during riots there in 2020.

"These courageous officers were attacked by left-wing street militants with weapons such as mortar fire, ball bearings, and blinding lasers," Cotton said in the letter. "A refusal to represent these Deputy Marshals would violate the Department’s long-standing practice — not to mention its moral duty — to defend law-enforcement officers when they’re sued for actions in the line of duty."

The DOJ missed Cotton's 3 p.m. Tuesday deadline to respond with a "satisfactory answer," prompting the senator to follow through with his threat to object to department nominees both in the Judiciary Committee and on the Senate floor.

Federal officers advance on demonstrators during a Black Lives Matter protest at the Mark O. Hatfield United States Courthouse Saturday, July 25, 2020, in Portland, Ore. (AP Photo/Marcio Jose Sanchez)

Though a single senator cannot block a presidential nominee indefinitely, Senates rules do allow one to delay confirmation of nominees for days or even weeks when they might otherwise have been confirmed by unanimous consent.

A DOJ spokesperson earlier told Fox News that Cotton's letter is being reviewed, noting that the department "represents or has paid for representation of over 70 federal employees who have been sued in connection with the events in Portland. Indeed, to date, the department has denied legal representation for only one federal employee in these cases."

Merrick Garland testifies before the House Judiciary Committee (CSPAN)

Merrick Garland testifies before the House Judiciary Committee. (CSPAN)

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But at least three U.S. Marshals say the DOJ has not made a final decision on their cases, a delay that has forced them to seek outside legal representation.

The DOJ did not immediately respond to a Fox News request for comment on the holds.