An “unspecified threat” caused a Delta jet arriving from London to be held at a remote area of Newark Airport this afternoon so cops could search the aircraft, sources said.

Delta Airlines Flight 69 touched down shortly after noon at Newark with 191 passengers and 11 crew members over what was termed an “unspecified threat,” a law enforcement source said.

The flight was met by members of the Port Authority Police Department, including patrol cops, Emergency Service Unit cops, members of the K-9 Unit and Air Craft Fire Rescue officers.

After the passengers were taken off the plane, cops assigned to the K-9 Unit swept the airplane and the luggage that had been taken off the aircraft.

The passengers were taken by bus to a remote location to await a Customs check, a source said.