SAN FRANCISCO/FRANKFURT (Reuters) - A Lufthansa flight bound for Germany from Texas was diverted to New York City on Monday due to a bomb threat, but a subsequent search of the aircraft found no explosive device, officials said.

Flight 441 destined for Frankfurt from Houston landed safely at John F. Kennedy International Airport at about 8:30 p.m. local time (1:30 a.m. GMT), said Steve Coleman, a spokesman for the Port Authority of New York and New Jersey.

The bomb threat was phoned into the airline’s headquarters. But a search of the plane was negative, the authority said on Twitter.

Calls to the Port Authority and the New York City Police Department remained unanswered.

All passengers had left the airplane and were put up at hotels, Lufthansa spokesman Joerg Waber said on Tuesday morning in Germany. He neither confirmed nor denied the bomb threat.

A passenger who was on the plane, who asked to remain anonymous, told Reuters the pilot announced two to three hours after takeoff that the flight had to be canceled and diverted to New York due to a bomb threat.

She said passengers on the plane remained calm and that police entered the aircraft upon landing.

The plane will be flown back to Germany without passengers, the Lufthansa spokesman said.

Operations at the New York City airport had not been affected by the incident, Port Authority spokesman Coleman said.