By Jan Wolfe

WASHINGTON (Reuters) -A U.S. judge on Wednesday said he was resuming his long-stalled court proceeding to determine whether Trump administration officials willfully violated a court order by deporting hundreds of men to El Salvador in March.

U.S. District Judge James Boasberg said he would demand sworn testimony from administration officials to determine whether they defied his March court order to turn around aircraft that were removing the men from U.S. territory.

"It seems that a factual inquiry is in order, and the best way to proceed would appear to be bringing in witnesses and having them testify under oath," Boasberg said during the hour-long status conference.

A three-judge panel of a federal appeals court halted the inquiry earlier this year. But a larger panel of appellate judges on Friday said Boasberg "remains free to require the government to identify the decision makers who directed the potentially contemptuous actions and to carefully consider next steps.”

Boasberg's remarks on Wednesday breathed new life into his standoff with the Trump administration over the limits of presidential power. By conducting the criminal contempt proceedings, which can result in fines or other forms of censure, Boasberg has drawn the ire of Trump allies, who say he has overstepped.

Boasberg asked the Justice Department to submit a proposal on November 24 outlining their proposed next steps. Boasberg also requested a similar proposal from lawyers who brought the litigation before him on behalf of the deported men.

The Justice Department has disagreed with Boasberg's interpretation of the appeals court order issued last week, asserting he lacks jurisdiction to conduct contempt proceedings. The Justice Department has also argued that the Trump administration did not willfully defy any court orders.

Boasberg has been hearing a lawsuit brought on behalf of alleged Venezuelan gang members removed from the U.S. under the rarely invoked Alien Enemies Act.

Boasberg in April concluded the Trump administration appeared to have acted "in bad faith" when it hurriedly assembled three deportation flights on March 15 at the same time that he was conducting emergency court proceedings to assess the legality of the effort.

The Venezuelan men at the center of the litigation were released from a Salvadoran prison this summer and returned to Venezuela as part of a U.S.-brokered prisoner swap.

(Reporting by Jan Wolfe in Washington; Editing by Daniel Wallis)