The Boeing 737-800 took off around 2 a.m. (7 p.m. EST) for Addis Ababa, according to the officials who spoke on condition of anonymity because they are not authorized to speak publicly.
Police officials ruled out terrorism as the cause of the crash and said it was likely weather-related. It has been raining heavily and lightning in Beirut since Sunday night.
Lebanese naval ships were scrambled to find the location of the crash.
About 50 of the passengers were Lebanese, the officials said.
