BEIJING - China's top observatory issued another alert for strong typhoon Krosa Saturday, as it moves towards China's southern coastal regions.

The National Meteorological Center (NMC) issued a yellow alert for Krosa Saturday, the second tier in the country's four-color weather warning system.

Krosa, the 29th typhoon to hit China this year, strengthened to become a strong typhoon at 11 pm on Friday, the NMC said.

At 5 am, its center was at the northern part of the South China Sea and about 605 kilometers east of the city of Wanning in southern China's Hainan province.

The NMC forecast that it will move westward at a speed of 10 to 15 km per hour towards Hainan as its force slowly weakens.

Local governments should take precautions against the typhoon while ships in areas on the route of Krosa should come back to ports, the NMC said.

On Friday, the State Flood Control and Drought Relief Headquarters announced a fourth-level emergency response, the lowest level, asking local authorities to monitor the typhoon, forecast its movement and ensure people's safety.