JERUSALEM (Reuters) -- An Israeli air force helicopter crashed in southern Israel on Tuesday killing its two pilots, the Israeli military said.

The BELL AH-1 Cobra helicopter was on a routine training flight when contact with it was lost. "The remains of the helicopter were discovered and no survivors were found," the army said in a statement.

It was not immediately clear what caused the crash. The air force has ordered an investigation into the incident and all Bell AH-1 Cobra helicopters have been grounded "until the circumstances of the accident are clarified," the army said.

Israeli media said the remains of the aircraft were found in a wheat field near an Israeli kibbutz. The army said that identification of the bodies was underway and that the families of the pilots had been notified of the incident.