A Waldorf man was shot and critically wounded yesterday while fleeing from two federal agents who were interviewing him in a firearms-trafficking investigation, authorities said.

"There was an altercation, and the subject was trying to elude the agents. . . . Then the subject was shot," said Mike Campbell, a spokesman for the U.S. Bureau of Alcohol, Tobacco and Firearms office in Baltimore. He said a pistol was found near the man.

The 20-year-old man, whose identity was withheld, was being interviewed along with another man by the ATF agents inside a town house in the 3000 block of Pilgrim Square in Waldorf about 2:15 p.m. when the shooting occurred, the spokesmen said.

Few details of the incident were available last night. Authorities would not describe the altercation, say how many agents fired their guns, how many shots were fired or in what part of the body the man was wounded. The man was reported in critical condition. He was taken first to Prince George's Hospital Center and was being transferred to another hospital last night. He had not been charged with a crime.

Craig Renner, a Charles County sheriff's spokesman, said it had not been determined whether the man fired any shots at the agents.

The sheriff's office is investigating the shooting. The incident is also under review by ATF internal affairs investigators.

Campbell, of the ATF, would not release information about the agents, both male, saying that the investigation was continuing.

The agents had gone to the Waldorf home to conduct interviews, Campbell said, and they did not have search or arrest warrants.

One man was inside the home when agents first entered, and the other--who was later shot--showed up later, Campbell said.

He said the gun-trafficking investigation was continuing and declined to divulge details about it.

Yesterday's shooting was the first involving ATF agents from the Baltimore office in about 10 years, Campbell said.