BEIJING, May 21 -- Rainstorms are expected to continue over southern China after killing at least 15 people and leaving seven missing since the weekend.

China's National Meteorological Center on Thursday continued to issue a rainstorm alert, but downgraded the warning level to the least serious level from Wednesday's yellow alert.

It said downpours will continue to hit some regions in Yunnan, Guangxi, Guangdong, Sichuan, Tibet and Taiwan on Thursday and Friday, warning local authorities to be on high alert against flooding and possible landslides.

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