BANGKOK — Thailand’s airlines are facing bans on new international flights and more inspections after the International Civil Aviation Organization flagged significant concerns about the country’s aviation safety, officials said on Friday.

The designation of Thailand as a “significant safety concern” has not been announced publicly by the aviation group, a United Nations agency, but governments were informed last week.

Japan has blocked new flights from Thailand since the decision, and South Korea is considering similar measures, officials said. Existing flights are not affected.

Thailand is one of the world’s top destinations, and its tourism industry is crucial to the economy, employing millions. The disruptions come ahead of Thailand’s new year holiday, known as Songkran, a heavy travel season when airlines typically add flights.