BEIJING, Aug 31 (Reuters) - China issued the highest typhoon warning on Thursday as Typhoon Saola crawled closer to the southeastern coastline, threatening Hong Kong and other major manufacturing hubs in neighbouring Guangdong province.

Chinese forecasters issued a typhoon red warning at 6 a.m. (2200 GMT). China's National Meteorological Center said Saola, currently located about 295km (183 miles) southeast of Guangdong province, will move northwest across the South China Sea at a speed of about 10 kph (6 miles per hour), gradually approaching the coast of Guangdong, then slowly weaken in intensity.

Wind speeds at 9 a.m. (0100 GMT) were clocked at 209 kph.

Saola will make landfall along the coast somewhere from Huilai County in Guangdong to Hong Kong on the afternoon to the night of Sept. 1, the center said.

China Railway has suspended several major train lines and Shanghai halted trains heading to Guangdong, according to local media.

As Saola edges closer to Guangdong, winds over the region will strengthen gradually, the Hong Kong Observatory said, noting that it will raise its strong wind Signal to No. 3 - the second lowest - later Thursday.

Saola will also bring storm surges to coastal low-lying areas, the Hong Kong Observatory noted, estimating Saola is currently about 440km (270 miles) from the metropolis.

Until 8 a.m. (0000 GMT) Friday there will be heavy rainfall in parts of Fujian and areas of Guangdong. Downpours could be 100-220mm (3.9 inches to 8.7 inches) in some areas.

Saola's winds are also affecting Fujian province, where videos on social media showed waves crashing along the coastline. The meteorological administration of Shishi city issued a typhoon blue warning.