The union representing workers at United Press International said yesterday that the news agency had closed one-person bureaus in nine small cities and laid off 35 or more employes.

The Wire Service Guild said the firings had come in two waves, with six people cut from the staff on Dec. 22 and the rest informed by mail yesterday.

No UPI spokesman was immediately available for comment.

UPI declared on Nov. 1 that it had reached an impasse in its negotiations with the guild, which represents 850 UPI journalists, technicians and clerical workers.

The news agency's owner, Mexican publisher Mario Vazquez Rana, said in a recent interview that UPI was losing $1 million a month.

Vazquez Rana acquired the news agency for $41 million in June 1986 under an agreement approved by a bankruptcy court.

On Nov. 3, the agency's three senior editors, Ben Cason, Barry Sussman and Kim Willenson, resigned after 10 months in their jobs, charging that they had been denied editorial control and no longer could guarantee the quality and integrity of the news report.

Bureaus that were closed were in Huntsville, Ala.; Reno, Nev.; Portland, Maine; Sioux Falls, S.D.; Wichita, Kan.; Morgantown W. Va; West Palm Beach, Fla.; Rockford, Ill; and Helena, Mont, the Guild spokesman said.

The guild said the agency also cut employes in Washington; Atlanta; Baltimore; Dallas; Boston; Kansas City; New Orleans; Providence, R.I.; Concord, N.H.; Omaha; Salt Lake City; Boise, Idaho; Louisville, and Honolulu.