U.S. Attorney Halsey B. Frank. Credit: Courtesy of the U.S. attorney's office

Maine’s top federal prosecutor will resign effective Sunday after working in the U.S. attorney’s office in Portland for more than two decades.

Halsey Frank, 62, of Portland announced Thursday that he had submitted his resignation to President Joe Biden at the request of acting Attorney General Monty Wilkinson, which is the standard practice when there is a change in administrations.

His successor has not been named, but members of the state’s congressional delegation have empaneled a group of Mainers from the public and private sectors to recommend a new U.S. attorney to the president.

First Assistant U.S. Attorney Donald E. Clark, who has served nearly 29 years as a federal prosecutor, will serve as acting U.S. attorney.

“Serving the people of Maine as U.S. Attorney has been the honor and privilege of my professional life,” Frank said in announcing his resignation. “I hope that my leadership has been positive for Maine and for the U.S. Attorney’s Office.”

Frank on Thursday outlined his work on Maine’s opioid crisis, combating violent crime, preventing elder fraud, promoting high school students’ understanding of religious tolerance and federal programs that have promoted greater cooperation among federal, state and local law enforcement and prosecutors.

U.S. Sen. Susan Collins recommended Frank for the job, and President Donald Trump nominated him on July 27, 2017. He was unanimously confirmed by the U.S. Senate on Oct. 4, 2017, and sworn in the following week.

The senator on Thursday described Frank as “a highly skilled and intelligent attorney.”

“From prosecuting scammers who robbed seniors of their hard-earned savings to fighting the opioid and drug abuse epidemic, Halsey’s efforts helped to keep Mainers safe,” she said.

Before coming to Maine in 1999, Frank worked as a federal prosecutor for the District of Columbia. He is a graduate of Boston University School of Law and Wesleyan University.

Frank has not made public his future plans.