US warplanes were scrambled to escort an Air France passenger jet flying from Paris to New York on Monday, following one of several threats against commercial aircraft that proved to be unfounded.

Flight AF022 landed at JFK airport without incident after being escorted to land by two F-15 fighter jets ordered to accompany the aircraft as a precaution by NORAD, the joint US-Canadian monitoring force.

The FBI said the plane was searched upon landing and the threat had turned out to be false.

"Out of an abundance of caution, Air France flight number 22 was escorted to John F. Kennedy airport by US Air Force fighter jets following a phone threat," FBI spokesman J. Peter Donald said in a statement.

"The plane has landed and has deboarded. There were no incidents or hazards reported on board the flight by either the passengers or its crew. The plane has been cleared," he added.

A person familiar with the incident said the fighter jets had been scrambled because of an inability to make immediate contact with the crew of the aircraft after the threat was first received.

The same source said the threat was one of as many as 10 made against US-bound flights on Monday.

All of the threats were believed to have been made by the same individual, the source told AFP.

A Saudi Arabian Airlines flight was also checked at JFK following a threat that turned out to be unfounded.

ABC News reported on its website that two flights headed to Newark, New Jersey -- a Delta Airlines flight from London and a United Airlines flight from Madrid -- were also targeted.

An American Airlines flight from Birmingham, England, heading to JFK was also affected. The threat against the plane was swiftly deemed to not credible and the plane landed as scheduled.

Authorities at Boston's Logan International Airport said a flight from Paris was also subjected to a threat that was in fact a "hoax," the Boston Herald newspaper reported, citing an airport spokesman.