Attorney General Dick Thornburgh said yesterday that the controversy over his handling of a leak inquiry was the result of a turf war waged by the Justice Department's internal watchdog unit.

Thornburgh said in an interview that the Office of Professional Responsibility (OPR) felt "crowded out of its jurisdiction" and "wanted to run its own investigation" into whether anyone in the department last year leaked information about an FBI probe of the office of Rep. William H. Gray III (D-Pa.), now House majority whip.

"Ultimately I acceded," Thornburgh said. "But I don't have a very sympathetic ear toward turf battles . . . I've made my feelings clear on turf battles, and I rely on my feelings being respected."

Aides to Thornburgh believe OPR staff members complained about the handling of the investigation to reporters as well as Sen. Joseph R. Biden Jr. (D-Del.), chairman of the Senate Judiciary Committee. Biden criticized Thornburgh for not referring the matter to OPR, which conducts administrative inquiries of alleged misconduct by department employees.

Thornburgh's deputy, Donald B. Ayer, who resigned in May after six months on the job, has said he left partly because Thornburgh tried to bypass OPR.

Michael E. Shaheen, who heads OPR, could not be reached for comment.

Thornburgh suggested yesterday that the controversy was overblown, saying, "This was a turf battle, come on, let's not kid ourselves."

After a television report about the Federal Bureau of Investigation probe of Gray, Thornburgh ordered a criminal investigation into whether the information was leaked by a department employee. He testified in a congressional hearing that "if it turns out there is not a threshold where criminal conduct is involved, then Mr. Shaheen's operation would, as in the normal situation, complete the investigation and recommend appropriate sanctions against those who can be identified."

But Thornburgh pronounced the matter closed after the FBI found no criminal wrongdoing, and authorized only a limited OPR investigation after complaints from Biden, Ayer and others. Thornburgh said he was reluctant to order the OPR investigation because he did not think it was needed.

Two of Thornburgh's closest aides were considered suspects in the original leak investigation, although a final review of the case by Solicitor General Kenneth W. Starr found no evidence that any department employee improperly released information.

Thornburgh said yesterday that there is some congressional interest in combining OPR with the Inspector General's office, a newly created unit in the department that handles administrative inquiries regarding employees who are not involved in criminal probes. But he said, "I'm not sure that this is wise thing to do," adding "I don't have it on the agenda at the present time."