Prime Minister Benjamin Netanyahu of Israel said a pilot tried to seize control of a flight from Dubai to Tel Aviv on Wednesday, stabbing the other pilot and forcing those aboard to retake the cockpit and land the plane in Saudi Arabia. According to Mr. Netanyahu, one of the pilots attacked the other midair in a possible attempt to crash the plane, Fly Dubai Flight 1073. He said a passenger and member of the crew broke into the cockpit to “neutralize” the pilot-assailant, while another crew member stabilized the plane.

The flight suddenly plunged thousands of feet and made an emergency landing at an airport in Tabuk, in northwestern Saudi Arabia. Israeli officials said the plane was carrying between 160 and 180 passengers. Fly Dubai said the passengers were all safe and accounted for. The flight’s pilot and co-pilot were treated in a hospital for injuries, according to the airport in Tabuk. The Saudi authorities arrested the suspected assailant, Mr. Netanyahu said.

Much of what happened aboard the flight remained unclear, including the cause of the sudden altitude loss and any possible motive. According to two Israeli security officials who spoke on condition of anonymity, the Israeli authorities are investigating the possibility that the altercation was an attempted attack on Israelis, among other lines of inquiry. Passengers described a scene of chaos as the aircraft dropped by around 17,000 feet in two minutes, according to Flight Radar24.