Israeli forces scrambled a pair of fighter jets on Tuesday to intercept a passenger plane after the pilot accidentally triggered a hijack alert.

The LOT Polish Airlines flight 155, operated by Bulgaria’s Electra Airways, was carrying 180 passengers from Warsaw to Tel Aviv when it transmitted an alert that it had been hijacked.

Bulgaria and Turkey also scrambled aircraft to respond to the serious threat. The Israeli military said the fighter jets had been dispatched due to “lack of contact with the aircraft”, but contact was soon established.

The aircraft landed safely in Bulgaria after the incident.

“The event has ended and contact has been restored with the airplane. There is no concern of a security incident,” the Israel Defence Forces said in a statement.

Bulgaria sent a MiG-29 to intercept the aircraft after it crossed the country’s northern border over the Danube following an alert triggered by Nato’s Air Policing mission over Bulgaria, according to Bulgaria’s public broadcaster BNT.

The passenger plane emitted transponder code 7500, which is used to send a signal of unlawful interference with an aircraft, including hijacking, it said.

Turkey also sent two F-16 fighter jets to accompany the aircraft on its onward route, BNT reported.

The alarm was triggered twice, once it entered Bulgarian airspace and again after it left Turkish airspace.

Bulgaria’s transport ministry blamed “a technical failure of the aircraft’s transponder, which transmitted a false [code 7500] signal of unlawful interference/hijacking”.

LOT spokesperson Krzysztof Moczulski said the incident was caused by a transponder that was incorrectly set, according to Polish state news agency PAP.

Mr Moczulski said Air traffic control later asked the pilot whether the emergency report still stood and the pilot confirmed that the alert was false.

He said it was “most likely [a] human error”, and said an investigation has been launched, calling it an “absolutely exceptional event”.