Crisis-hit Malaysia Airlines passengers will now have to hand-carry their electronic cigarettes and not put them in their check-in baggage following a new safety alert.
However, this ruling does not alter the no-smoking rule in the passenger cabin.
The new directive followed a safety alert by the Federal Aviation Administration, recommending that airline operators ensure all passengers carry e-cigarettes in the aircraft's cabin, the airlines said in a statement.
"Following recent fire incidents involving e-cigarettes, the FAA issued a safety alert recommending all airline operators to ensure e-cigarettes (also called personal vapourisers or electronic nicotine delivery) be carried by passengers exclusively in the cabin of the aircraft and not in checked baggage," the statement said.
"Carriage of e-cigarettes in the passenger cabin addresses this safety risk by ensuring that if an incident does occur, it can be immediately identified and mitigated," it said.
Recently, an overheated e-cigarette sparked a fire in a piece of luggage at the Los Angeles International Airport.
Malaysia Airlines is suffering loss after witnessing a difficult period last year.
Its Flight MH370 with 239 people aboard lost contact on March 8. No trace of any wreckage has been found so far.
Another flight MH17 was shot down by a missile over eastern Ukraine on July 17, killing all 289 people aboard.
In April, a Bangalore-bound Malaysia Airlines plane with 166 people on board turned back shortly after takeoff due to problem in its landing gear.