VIENNA, Austria (AP) _ A Swissair flight from Bucharest to Zurich made an unscheduled stop in Vienna today after an anonymous caller in Bucharest said a bomb was on board, officials said.

The Airbus A320 carrying 68 people flew on to Switzerland nearly four hours later after no bomb was found, said Mario Sante, a spokesman for Vienna International Airport.

In Romania, the Transport Ministry said the call was received a half-hour after Flight 461 left at 8:42 a.m local time. The plane landed in Vienna less than an hour later, Sante said.

Police removed all the baggage and mail and questioned the passengers.

The airline had no indication of a motive behind the bomb threat or where it came from, said Swissair spokesman Erwin Schaerer.

Romania's central bank governor, Mugur Isarescu, was among the 32 Romanian passengers aboard, on his way to Washington for a meeting of the International Monetary Fund and the World Bank, a Bucharest radio station reported.