MIAMI (AFP) - An American family's holiday reunion ended in tragedy Sunday (Dec 24) when their light plane crashed in Florida, killing all five people aboard, the local sheriff's office said.

The crash killed the pilot John Shannon, 70, his two adult daughters, his son-in-law and a family friend, the Polk County Sheriff said.

"This is a tragedy any time, but it is so much worse because it happened on Christmas Eve," Sheriff Grady Judge said in a news release.

Investigators said the twin-engine Cessna 340 took off from Bartow Airbase, near Tampa, about 7.15 am (8.15pm Singapore time) bound for Key West, but it went down near the end of the Bartow runway.

While the cause of the incident is under investigation, "it was very foggy at the time," the sheriff's office said, adding that a fire followed the crash.

"All of the victims perished upon or immediately after impact," it said.

In addition to Shannon, the statement said the victims are believed to be Olivia Shannon, 24, a university student; Victoria Shannon Worthington, 26, a school teacher; her husband Peter Worthington, Jr, a law student; and family friend Krista Clayton, 32, a teacher.

The Worthington couple had "arrived in town yesterday for the holidays, from Baltimore, where they live. Krista joined the family on the trip," the news release said.

On his website, Shannon said he began practising law in 1975, and had focused on "personal injury and death" cases.