Four persons, including two small children of a circus trapeze performer, were injured yesterday in a fire that broke out in the performer's trailer outside the Capital Centre, authorities reported.

Nuran Vanreenen, 24, the wife of Circus Vargas trapeze performer Rodney Vanreenen, was seriously injured, along with the couple's 2-year-old son, hospital officials said last night.

The Vanreenens' 2-month-old son and a concessionaire identified as Gerhard Homeyer, 41, of Hollywood, Calif., were also injured. Homeyer was hurt when he tried to rescue Nuran Vanreenen and the children, according to Prince George's County fire department spokesman Tony DeStefano.

The Vanreenens' 22-foot travel trailer was parked in the north parking lot of the Capital Centre, about 100 yards from the arena, when the fire was detected about 11:30 a.m., DeStefano said.

A circus spokesman said a performance was under way in the arena at the time.

The cause of the blaze was not known last night, DeStefano said. He said it caused about $22,500 in damage to the Vanreenens' trailer and to two adjacent trailers.

DeStefano said an inspector from the fire department who was making a routine inspection spotted the smoke from the trailer. After calling for fire and rescue equipment, he joined others in the area in using extinguishers to try to quell the blaze, DeStefano said.

Nuran Vanreenen was taken by Maryland state police helicopter to the burn unit at Washington Hospital Center with smoke inhalation and second-degree facial burns, DeStefano said.

He said Ashley Vanreenen, 2, who was burned on his face and incurred smoke inhalation, was taken first to Prince George's Hospital Center, then to Children's Hospital. He was listed in serious condition last night.

Lucian Vanreenen, 2 months, was listed in good condition at the hospital after incurring burns and smoke inhalation.

Mike Gorman, a spokesman for the circus, said Rodney Vanreenen, a member of the Ayak Brothers trapeze act, did not perform in the 11 a.m. show because of the fire.