BEIJING - China's maritime authority on Saturday issued a yellow wave warning as Typhoon Wutip, the 21st of the season, approaches land.

According to the National Marine Environmental Forecasting Center, Wutip is expected to make landfall on Vietnam's central coast on October 1.

The center warned that, from Saturday night to Sunday, waves as high as 5 to 7 meters may occur in the South China Sea, and waves measuring up to 3 meters may be spotted near Hainan's eastern coastal areas.

Wutip is expected to strengthen into a violent typhoon affecting areas in the western part of the South China Sea and Hainan's southern coast.

The center urged coastal authorities to take precautionary measures and pay close attention to changes in sea routes as tourism will increase in Hainan during the upcoming National Day holiday, which begins October 1.

China has a four-tier color-coded weather warning system, with red representing the most severe weather, followed by orange, yellow and blue.