A Lebanese diver gathers debris from the Boeing 737-800 that crashed in the sea off the Lebanese coast shortly after takeoff. (Bilal Hussein/Associated Press)

The pilot of an Ethiopian Airlines plane that crashed into the Mediterranean Sea shortly after taking off in stormy weather flew in the opposite direction from that recommended by the control tower, Lebanon's transportation minister said Tuesday.

The tower "asked him to correct his path but he did a very fast and strange turn before disappearing completely from the radar," Transportation Minister Ghazi Aridi told The Associated Press.

The Boeing 737-800 had taken off from Beirut airport Monday during thunderstorms and lightning. It went down 3½ kilometres off the Lebanese coast at roughly 2:30 a.m. local time, only minutes after takeoff en route to Addis Ababa, the Ethiopian capital.

All 90 people, including a Canadian passenger, are feared dead. Search-and-rescue teams have so far recovered more than 20 bodies and are looking for the plane's black box and flight data recorder.

"Nobody is saying the pilot is to blame for not heeding orders," Aridi said, adding: "There could have been many reasons for what happened.…Only the black box can tell."

It is not clear why the pilot did not correct his flight path or whether he could. The Boeing 737 is also equipped with its own onboard weather radar, which the pilot may have used to avoid flying into storms.

The Lebanese army also said the plane was on fire shortly after takeoff. A defence official said some witnesses reported the plane broke up into three pieces. Officials have ruled out terrorism as a cause of the crash, without elaborating.

Beirut air traffic control was guiding the Ethiopian flight through the thunderstorms for the first two to three minutes of its flight, an aviation analyst familiar with the investigation told The Associated Press.

The official said this was standard procedure by Lebanese controllers to assist airliners leaving the airport in bad weather.

Ethiopian Airlines said the pilot had more than 20 years of experience.

With files from The Associated Press