POMONA, Calif. — A pilot and three occupants aboard a single-engine Piper are recovering from injuries Monday following a plane crash at the Pomona Fairplex during the National Hot Rod Association Finals.

Two of the victims suffered critical injuries and two had moderate injuries, a spokesperson for the Los Angeles County Fire Department told City News Service Sunday. All four were taken to a hospital.

No one was injured on the ground.

The plane crashed at 11:09 a.m. Sunday in an RV area where fans and spectators stay for the NHRA races. The plane crashed next to an RV where the family of Ron Capps, one of the NHRA drivers, was staying. No one in the RV area was injured in the crash, authorities said.

The RV area at the drag strip is at 1101 W. McKinley Ave. Authorities said the plane struck several vehicles on the ground.

The races were interrupted for about two hours for firefighters and police to respond to the crash. The NHRA cars were removed from the drag strip during the delay.

"Our thoughts are with everyone involved in this incident," the NHRA said in a statement released Sunday.

NHRA Top Fuel driver Antron Brown said after the race he waited in his hauler for the races to resume. The crash happened during the first round of eliminations in Top Fuel. Brown won the Top Fuel event and the Top Fuel championship at Pomona.

''I didn't want to sit there in the moment. When they told us we could get out of the cars, then they told us really, really quick that we could go back. I went into hibernation,'' Brown said. ''When I'm usually out in the crowds signing autographs, I didn't. I actually stayed in my lounge for the first time and I laid on the couch with a hat over my head, just taking my mind away from everything. Just get ready for another qualifying round, that's what I told myself.''

The fire department was on the scene to contain and address spilled fuel from the airplane. The Federal Aviation Administration was notified and investigators from the National Transportation Safety Board were on the way to conduct an investigation into the collision.

The crash prompted the NHRA to pause the competition, but the event started up again at about 1 p.m. Sunday.

Pomona police urged anyone with information regarding the crash to call them at 909-620-2156.