North Vietnam is holding the remains of 400 U.S. servicemen killed in Vietnam and is refusing to turn them over to U.S. authorities, Rep. Lester L. Wolff (D-N.Y.) charged yesterday.

At a Capitol Hill news conference Wolff reported that (U.S. intelligence has interrogated a former Vietnamese mortician who described the bodies and identified the site where they are held in Hanoi.

On a Jan. 15 trip to Hanoi, a U.S. congressional delegation headed by Wolff raised the issue of the 400 bodies with Vietnamese Deputy Foreign Minister Phan Hien and Ambassador Vu Hoang.

"The Vietnamese immediately refused to countenance the story, and declined to permit on-site inspection," Wolff said.

However, one delegation member, Rep. George Danielson (D-Calif.), said he is not convinced North Vietnam is holding the bodies.

Danielson said the report is based on the testimony of a sole witness -- the former Vietnamese mortician, who, he said, may have had a variety of motives in presenting his account.

"I am not yet convinced," Danielson said.

"This is a highly emotional issue. You must look at the evidence cold-bloodedly. The acts are that all of this rests on a story told by a single refugee."

Wolff presented a representive of the Defense Intelligence Agency, identified only as Adm. Tuttle.

Tuttle told the press conference: "There is no question in my mind. I am totally convinced. As far as I am concerned, the evidence is irrefutable."