MOSCOW (Reuters) - A Russian passenger plane left Moscow for Havana on Thursday without any sign of former U.S. spy agency contractor Edward Snowden on board, witnesses said.

Cuba is considered a possible destination for Snowden on his way to Ecuador, where he is seeking asylum.

The 30-year-old American is wanted in the United States on espionage charges and is thought to have remained in the transit area of Moscow's Sheremetyevo airport since flying in from Hong Kong on Sunday.

Russia carrier Aeroflot confirmed the plane's departure but declined comment on the passenger list. Airline sources had said earlier on Thursday that Snowden had not registered foe the flight.

(Reporting by Lidia; Kelly and Maxim Shemetov, Writing by Timothy Heritage, Editing by Steve Gutterman)