SALVADOR, Brazil, May 3 (UPI) -- Six people, including four British nationals, are missing after a small aircraft vanished and likely crashed in Brazil, officials say.

Britain's Foreign Office said British citizens Alan Kempson, Sean Woodall, Ricky Every and Nigel Hodges were all on board a small plane that disappeared off Brazil's northeastern coast Friday, the BBC reported Saturday.

Witnesses said they saw the plane lose power and begin to go down, but searches had not found any wreckage or survivors.

The business manager of Aero Star, the airline that operated the aircraft, said the plane was in perfect condition when it left Salvador.

"It was flying perfectly," manager Ellen Duarte said. "The pilot said he was making a visual approach to the airport, and that was the last we heard."

The Daily Mail reported the company's Web site said the plane's two pilots, who are also missing, had more than 10,000 hours of flying experience altogether.