A plane carrying up to 18 people, including a group of eight Italians, crashed into the sea close to a group of Venezuelan islands after reporting engine trouble, officials said.
The plane was flying to the Los Roques archipelago from Caracas but reported engine trouble and never arrived at its destination, an air rescue worker said.
Rescue workers in speed boats and helicopters searched for the twin-engined aircraft. The plane was originally to carry 14 people, but four more boarded just before takeoff, said Gen. Antonio Rivero, who heads Venezuela's civil protection agency.
Rain and strong waves have "made the search for the plane more difficult," Rivero told a local television network.
A spokesman at the Italian Foreign Ministry said eight of the people on board the plane were Italians. He gave no further details.
Civil protection said in a statement it was unsure of the nationality of one of the passengers after having said earlier there was an American on board.
Air rescue and civil protection officials said the pilot reported engine problems just before contact was lost. They said the search had not yet turned up the plane, a Czech-made 19-seat LET L-410.
The non-profit agency Aviation Safety Network reports on its Web site that a Transaven-operated aircraft made an emergency landing after taking off from Caracas for Los Roques in 2005.
In 2002, another Transaven plane made an emergency landing in the sea while flying to the same islands, according to Venezuelan media. Thirteen people on board were uninjured.
Los Roques is a national park off the coast of Venezuela, renowned for white sand beaches and crystalline water that is popular with European and US tourists.