BUFFALO — Western New York’s top federal prosecutor, an appointee of President George Bush, said Tuesday he will resign at the end of next week.

U.S. Attorney Terrance Flynn said he will go back to private practice as a partner with the Harris Beach law firm, working mainly out of its Buffalo office.

Bush nominated Flynn as U.S. attorney for the western district of New York in December 2005 to replace Michael Battle, who took a job with the Justice Department in Washington.

Barack Obama will nominate a replacement for Flynn. There is no word yet on who that will be.

New York’s large western district covers 17 counties from Buffalo to Rochester and has 2.8 million residents.

“I’ll miss the people but it’s time for President-elect Obama to choose a new U.S. attorney,” Flynn, 45, said before a news conference Tuesday in Buffalo. He planned to meet with reporters in Rochester later in the day.

Flynn, a former trial lawyer, called his three years in the federal job exhilarating and said he was most proud of his office’s recovery of more than $124 million for taxpayers and victims of health care and other fraud.

He also oversaw numerous prosecutions of child predators and human trafficking cases, teaming regularly with state, local and Canadian authorities.

“No U.S. attorney is fully ready for the breadth of the issues ... You have to be ready every day with your team of people to react,” he said.

Among the office’s unfinished business is the prosecution of former Niagara Falls Mayor Vincenzo Anello, who was indicted in November on federal corruption charges tied to payments from a businessman before he became mayor in 2004. Anello has pleaded not guilty. Meanwhile, racketeering charges are pending against 12 members of Operating Engineers Local 17, a construction union whose leaders deny allegations they used threats and vandalism to secure work.

Flynn has said his concern for crime victims was motivated in part by witnessing the 9/11 terror attacks. He was staying at a hotel near the World Trade Center in New York City at the time.

“I saw people jumping from the tower to avoid being burned alive,” Flynn told The Buffalo News. “I saw the looks on their faces. .. Something like that, you never forget. It becomes part of the fabric of your personality.”

At Harris Beach, Flynn expects to work on a variety of civil and criminal litigation.

He said the Justice Department will likely name an interim U.S. attorney to take over until a permanent replacement has been approved by the U.S. Senate.