More than 7,000 fishing vessels have been called to harbour, with Typhoon Muifa's winds reaching 162km/h (100mph) and generating 36ft (11m) waves at sea.

At least 140 flights have been cancelled and rail services disrupted.

Muifa is due to brush Shanghai rather than make landfall in Zhejiang province or Shanghai as previously expected. Meteorological officials said Muifa could still make landfall near Qingdao city, in Shandong province, on August 7.

China's National Marine Environmental Forecasting Centre has upgraded its warning to a red alert - the highest possible - for shipping in the East Sea.

Muifa has already battered the Philippines - where it caused flooding - Taiwan and Japan's southern island of Okinawa, which was hit by blackouts.

The typhoon is being described as the most serious to threaten the region since 2005, when Typhoon Matsa killed 19 people, including seven in Shanghai.

Shanghai's rail authorities are planning inspections of local high-speed rail networks and warned that some services could be halted or delayed depending on the storm's severity.

On August 4 night, Muifa was downgraded from a super typhoon - measuring 185km/h (114mph) or more - to a severe typhoon, but it is still expected to be one of the most powerful storms to hit China in recent years.