BEIJING, July 29 (Xinhua) -- China's flood control authorities on Sunday called for intensified efforts on disaster prevention with the approach of tropical storms Saola and Damrey.

In a statement on its website, the State Flood Control and Drought Relief Headquarters urged observatories and local authorities to enhance monitoring and make sure major facilities in cities could resist strong winds and possible flooding as the tropical storms were still strengthening and might land on the country.

Saola developed into a strong tropical storm at 2 p.m. Sunday. It was located 620 km southeast of the southern tip of Taiwan at 5 p.m., packing winds up to 90 km per hour at its center, the National Meteorological Center said.

The tropical storm will continue strengthening and is expected to move northwestward at a speed of 10 km per hour, the observatory forecast.

Meanwhile, Damrey, located 1,220 km southeast of Tokyo at 5 p.m. Sunday, was expected to move northwestward at a speed of 10 to 15 km per hour.