Image caption Boeing plans to raise production of the 787 Dreamliner to 12 per month by 2016

Fifteen airlines have been warned about the risk of ice forming on Boeing's new 747-8 and 787 Dreamliner planes.

The issue - affecting some types of engines made by General Electric when planes fly near high-level thunderstorms - prompted Japan Airlines to cancel two international routes.

There have been six incidents since April when aircraft powered by GE engines lost power at high altitude.

These are the latest technical issues to hit the Dreamliner.

They saw the entire fleet being grounded earlier this year following battery problems.

The Boeing 747-8 series and the new 787 Dreamliner are the only types of aircraft affected by the high-altitude icing issue.

The new warning was given to airlines including Lufthansa, United Airlines and Japan Airlines.

It says aircraft with the affected engines - GE's GEnx - must not be flown within 50 nautical miles of thunderstorms that may contain ice crystals.

As a result, Japan Airlines (JAL) has decided to withdraw Dreamliners from service on the Tokyo-Delhi and Tokyo-Singapore routes.

"Boeing and JAL share a commitment to the safety of passengers and crews on board our airplanes. We respect JAL's decision to suspend some 787 services on specific routes," a Boeing spokesman said, according to Reuters news agency.

A GE spokesman told the agency the aviation industry was experiencing "a growing number of ice-crystal icing encounters in recent years as the population of large commercial airliners has grown, particularly in tropical regions of the world".

He said GE and Boeing were hoping to eliminate the problem by modifying the engine control system software.

British airways use Rolls Royce engines on their Dreamliners. They are not affected by the warning, says the BBC's Ben Geoghegan.

Orders increase

The 787 Dreamliner has suffered a series of technical and safety problems in recent months.

In January, its entire fleet was temporarily grounded. The decision came after a fire broke out on one of JAL's Dreamliners, and an All Nippon Airways (ANA) flight was forced to make an emergency landing because of a battery fault and a fire in one of the electrical compartments.

Image caption Battery problems resulted in the entire Dreamliner fleet being grounded earlier this year

In July, a fire broke out on a 787 jet operated by Ethiopian Airlines while it was parked at Heathrow airport. It was traced to the upper rear part of the plane where a locator transmitter is situated.

Then in August, ANA said it had found damage to the battery wiring on two 787 locator transmitters during checks. US carrier United Airlines also found a pinched wire during an inspection of one of its six 787s.

Despite the issues, the Dreamliner is still considered to be one of the most advanced planes in the industry and remains popular.

Boeing has received orders for more than 1,000 jets since its launch.

Last month, it announced plans to raise production of the 787 Dreamliner to 12 per month by 2016.

That would be an increase from its target for the end of this year of 10 planes a month.