CLEVELAND (AP) _ A city transit bus veered off the road and smashed into a utility pole and a chain-link fence, killing a teen-age boy and injuring 23 other passengers, authorities said.

City and transit authority police today were trying to determine the accuracy of witness accounts that a car caused the crash Tuesday night by swerving into the path of the bus, then speeding away.

The front of the Greater Cleveland Regional Transit Authority bus was heavily damaged. Part of the broken utility pole rested on a nearby car that was demolished in the accident near downtown.

City police were questioning the driver of the demolished car, who appeared to be uninjured. It was unclear whether that car played a part in the accident, authorities said.

The bus driver was admitted in fair condition with a broken leg, said Maria Tayek, spokeswoman for St. Vincent Charity Hospital and Health Center.

In all, five people were admitted to area hospitals, none in serious condition, and 18 were treated and released. Officials did not know how many passengers were on the bus.

The Cuyahoga County coroner's office identified the dead boy as Bernard Murry of Cleveland. The 13-year-old was dead on arrival at St. Vincent Hospital, said Dr. Carla Streep O'Day, director of emergency services. She said it appeared that a post from a metal fence which the bus hit pierced his side.

Passenger Robert Carter said he saw a dark-colored station wagon near the bus.

''I think I saw someone get out of that car and run away. Then it was gone,'' he said.

Sgt. Lou Narducci of the transit police said witness accounts varied, leaving police unable to determine the cause of the accident.