The Civil Aviation Authority of Vietnam said 118 flights operated by Vietnamese carriers will be affected by the Chinese live-fire drills, with 36 operated by Vietnam Airlines and the rest by Vietjet Air.

With flights from Vietnam to South Korea and Japan, a Vietnam Airlines spokesperson said aircraft would have to fly into China's inland area to avoid Taiwanese airspace, adding 10-15 minutes to flying time.

With flights to the U.S. the carrier was forced to change its route by flying over the Philippines, with the detour adding 35 minutes.

Flights between Vietnam and Taiwan remain operational.

A representative of Vietjet Air said the carrier has changed its routes for a series of flights connecting with Japan and South Korea.

In addition to adjusting flight routes, some flights may be delayed, with detours increasing fuel costs.

China on Thursday launched in six areas around Taiwan, a day after a visit by U.S. House of Representatives Speaker Nancy Pelosi to the island in what was described as the highest-ranking U.S. official to do so in 25 years.

On Wednesday, China warned airlines operating in Asia to avoid flying in areas around Taiwan from Thursday to Sunday, prompting several Asian airlines to adjust their routes.

Vietnam resumed international flights to the U.S. and Northeast Asian countries in January.

Source: VNE