The typhoon made landfall on the Philippines' Calayan Island, part of the sparsely populated Babuyan chain, at 3:00 pm (0700 GMT), according to the Philippine weather service.

As of 5:00 pm (0900 GMT), maximum sustained winds of 215 kilometres per hour (134 mph) were reported at the storm's centre, with gusts reaching as high as 295 kph, the national weather service said.

"I woke up because of the strong wind. It was hitting the windows, and it sounded like a machine that was switched on," said Tirso Tugagao, a resident of Aparri, a coastal town in northern Cagayan province.

On Calayan Island, at the storm's centre, information officer Herbert Singun told AFP chunks of a school roof had been ripped off and landed on an evacuation centre about 30 metres (yards) away, leading to one minor injury.

"Can you see those coconut trees swaying in the distance?" he asked over video chat.

"There were eight of them before. Now only four are still standing. That goes to show how strong this typhoon is."

Just over 10,000 Filipinos were evacuated across the country, with schools and government offices closed Monday in the Manila region and across 29 other provinces.

A much larger operation will take place in China's Shenzhen, where authorities said late Sunday they planned to move hundreds of thousands of people from coastal and low-lying regions.

Multiple other cities in Guangdong province announced classes and work would be cancelled, and public transportation suspended because of the typhoon.

Hong Kong-based Cathay Pacific said it expected to cancel more than 500 flights as Ragasa threatened the financial hub.

A spokeswoman for the airline said passenger flights in and out of Hong Kong International Airport would be halted from 6:00 pm Tuesday, "resuming during daytime hours on Thursday".

- 'Extremely torrential' -

In Taiwan, the state weather service predicted a chance of "extremely torrential rain" in the country's east.

"Its storm radius is quite large, about 320 (kilometres). Although the typhoon's centre is still some distance away, its wide, strong wind field and outer circulation are already affecting parts of Taiwan."

James Wu, a local fire department officer, told AFP that evacuations were ongoing in mountainous areas near Pingtung.

"What worries us more is that the damage could be similar to what happened during Typhoon Koinu two years ago," he added, describing a storm that saw utility poles collapse and sheet-metal roofs sent flying into the air.

Philippine government weather specialist John Grender Almario said Sunday that "severe flooding and landslides" could be expected in the northern areas of the main island Luzon.

The threat of flooding from Ragasa comes just a day after thousands of Filipinos took to the streets to protest a growing corruption scandal involving flood control projects that were shabbily constructed or never completed.

The Philippines is the first major landmass facing the Pacific cyclone belt, and the archipelago is hit by an average of 20 storms and typhoons each year, putting millions of people in disaster-prone areas in a state of constant poverty.

Scientists warn that storms are becoming more powerful as the world warms due to the effects of human-driven climate change.

bur-cwl/reb/mtp

CATHAY PACIFIC AIRWAYS