Sanya in South China's Hainan province upgraded its typhoon warning signal from orange to red, the most severe of the four-tier system, at 6:36 am on Sunday as Typhoon Kajiki is forecast to make landfall in the city between afternoon and evening, according to the Sanya Meteorological Observatory.

In response, the city has implemented a suspension of citywide classes, work, business operations, tourist attractions and transportation. Only entities and individuals involved in safeguarding public welfare and basic services are exempted.

Typhoon Kajiki, the 13th typhoon of this year, intensified from a severe tropical storm to a typhoon at 2 am on Sunday, according to the Hainan Meteorological Bureau.

The typhoon is moving west-northwest at a speed of 15 to 20 kilometers per hour and is rapidly gaining strength. It is expected to approach the southern coast of Hainan Island and make landfall in Sanya between Sunday afternoon and evening as a severe typhoon. Afterward, it is likely to move toward the central and northern coastal areas of Vietnam.

Over the next 12 hours, average wind forces in coastal and inland areas of Sanya are forecast to reach up to Force 12 on the Beaufort scale, with gusts reaching Force 13 to 15. Heavy rainfall and strong thunderstorms are also expected.