China's flood control authority on Thursday launched an emergency response for tropical storm Nock-Ten, which is expected to land at the country's southern coastal regions on Friday night or Saturday morning.

Dark clouds are seen over the sky in Haikou, capital of south China's Hainan Province, July 27, 2011. [Xinhua]

Nock-Ten, which killed at least 31 people in the Philippines, is the eighth storm and the most powerful one to hit China so far this year. It will make landfall over the coastal regions of western Guangdong and eastern Hainan Province, the State Flood Control and Drought Relief Headquarters (SFDH) said.

As of 10 a.m. Thursday, the center of the storm was 600 kilometers southeast off Hainan's Wenchang City, packing winds up to 82.8 km per hour.

The storm will continue to move northwestward at a speed of 20 km per hour, it said.

The storm may bring heavy downpours to Hainan and other regions in south China over the next three days, it forecast.

The SFDH urged local authorities to enhance monitoring, issue early warnings to the public and intensify safety checks in areas vulnerable to floods and geological disasters.