After a lengthy evacuation operation, police in Reykjavik said a search of the plane was under way and that no explosives had been found so far, but that the search would continue for several hours.

"There was an anonymous call saying that there was an explosive device on the plane, which was already in the air," Aeroflot spokeswoman Irina Dannenberg said. "The pilot took the decision to land the plane and it landed safely."

A spokesman for Iceland's Keflavik airport said 253 people were on board the flight from John F. Kennedy airport. A duty officer at Moscow's Sheremetyevo airport, the aircraft's destination, identified it as Aeroflot Flight 103.

A New York law enforcement official familiar with the situation told Reuters that a bomb threat call was made to JFK airport officials after the plane left, saying there were five pieces of luggage full of explosives on the plane.

Russian news agency Interfax, citing an unnamed source, said the anonymous caller said the explosives would detonate upon arrival in Moscow.

An official at Iceland's Civil Protection Department said passengers underwent security checks before entering the airport. Aeroflot said it was sending another aircraft to bring them to Moscow.

Emergency teams also searched an aeroplane in the city of Voronezh, 500 km (300 miles) south of Moscow, for explosives on Thursday after an anonymous phone call was made to the city's airport, but no bomb was found, state-run RIA news agency reported.

A suicide bomb blast in the international arrivals area at Moscow's Domodedovo airport in January 2011 killed 37 people. Islamist insurgents in Russia's North Caucasus claimed responsibility.

Suicide bombers identified as women from the North Caucasus blew up two planes on domestic Russian flights almost simultaneously in August 2004, killing all 90 people aboard in part of a series of attacks on targets around Russia. (Additional reporting by Simon Johnson in Stockholm and Chris Francescani in New York; Writing by Thomas Grove and Steve Gutterman; Editing by Jon Hemming and Pravin Char)

• A Permanent Economic Emergency