The pilot of an Ethiopian Airlines plane that crashed into the sea flew in the opposite direction from the path recommended by the control tower after taking off from Beirut in thunderstorms, Lebanon's transportation minister said yesterday.

But he cautioned against making any conclusions about the cause of the crash, saying investigators still needed to find the black boxes.

All 90 people on board are feared dead after the plane, bound for Ethiopia's capital, Addis Ababa, crashed into the Mediterranean minutes after takeoff at around 2.30am on Monday.

Transport minister Ghazi Aridi said the pilot initially followed the tower's guidance, but then abruptly changed course and went in the opposite direction. "They asked him to correct his path but he did a very fast and strange turn before disappearing completely from the radar," Mr Aridi said.

It was not immediately clear why the pilot veered off the recommended path. Like most other airliners, the Boeing 737 is equipped with its own onboard weather radar, which the pilot may have used to avoid flying into thunderheads rather than following the flight tower's recommendation.

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

Girma Wake, the chief executive of Ethiopian Airlines said the minister's comments were premature.