The storm, the fourth this year over the East Sea, also known as the South China Sea, would bring especially heavy rain to the region between Thanh Hoa and Quang Binh provinces on Saturday and Sunday, the National Center for Hydro-Meteorological Forecasting said on Tuesday.

As of 7 a.m. Wednesday the storm lay centered 620 km east of the Paracel Islands, and packed winds of 60-75 kph.

In the next 24 hours it is expected to move west at 30 kph and intensify, the center said on Wednesday.

The storm would lie centered directly above the Paracel Islands by 7 a.m. Thursday with winds of up to 90 kph, it added.

In the next 48-72 hours, the storm is expected to make landfall between Thanh Hoa and Quang Binh before weakening into a tropical depression.

The storm, which is known as Jenny in the Philippines, pushed across eastern Luzon on Tuesday. It weakened to a tropical depression but has regained tropical storm status since emerging in the South China Sea.

AccuWeather, an American provider of commercial weather forecasting services, said landfall is possible in China's island Hainan on Friday, followed by another landfall in northern Vietnam on Saturday.

Earlier this month Vietnam was struck by storm Wipha, which brought heavy rains, floods and landslides that left at least 10 dead and 11 missing.

Annually the country is hit by up to 10 tropical storms during the monsoon season between July and October. Four are expected this year.

Natural disasters, mostly floods, storms and landslides, killed 181 people last year and left 37 others missing and caused losses of around VND20 trillion ($858 million).