A small plane crashed in a hospital parking lot in Watsonville, Northern California, killing four people on board, authorities said on Friday.

The plane skidded into an unoccupied medical office building, but nobody on the ground or in the hospital was hurt in the crash, according to the Watsonville Community Hospital.

The crash occurred shortly after the single-engine, 37-year-old Mooney M-20 took off from Watsonville Municipal Airport Thursday night, authorities said.

Authorities on Friday had not identified the people who died, but local media outlets were reporting them to be a couple and their two children en route to a family reunion.

"Because of the quick response by the Fire Department, no evacuation was necessary," said a spokeswoman for Watsonville Community Hospital. "All areas of the hospital remain operational, including our emergency room."

The National Transportation Safety Board had dispatched investigators to the scene on Friday, trying to determine the cause of the crash.