Three people have been killed in southern California after a helicopter crashed into a house shortly after taking off.

The aircraft, a four-seat Robinson R44, landed in a gated community in Newport Beach, some 72 km south east of Los Angeles, at around 1.45pm.

A neighbour who witnessed the crash told local television that he saw three people in the wreckage, and the pilot lying injured on grass near the aircraft.

Two other people were injured in the incident, officials said, but it is unclear how many of the victims were on board the aircraft.

Four people were in the helicopter according to the Federal Aviation Administration.

"The three people were all crunched in there together," a neighbour who witnessed the crash said. "One I could see moving an arm.

"We tried to pry them out but we didn't want to touch them."

Another neighbour said she saw no fire and believed that the helicopter had attempted a landing and clipped a roof in the neighbourhood.

She said her house shook when the crash happened.

The house that was hit was reportedly up for sale, reports said.