At least 12 people have died after Super Typhoon Mangkhut ripped through northern areas of the Philippines with wind gusts reaching 305kph.
The typhoon was the strongest storm the planet has seen this year before it made landfall on Cagayan province at 1:40 am local time.
The dead and injured included an infant and another child, presidential adviser Francis Tolentino said.
They were among four people killed in a landslide in the province of Nueva Vizcaya.
Mr Tolentino said about 87,000 people had been evacuated from high-risk areas.
A body was also found in a river in Manila, according to police.
In neighbouring Taiwan, a woman died after being swept out to sea.
A resident walks beside a toppled basketball court after Typhoon Mangkhut barrelled into Tuguegarao city in the north east of the Philippines, 15-09-2018. Image: Aaron Favila/AP/Press Association Images
The storm knocked out power as it tore across the northern part of Luzon Island - an area which is home to around 10 million people, many of whom live in flimsy wooden homes.
More than 100,000 evacuees took refuge in emergency shelters following a mass evacuation of coastal areas.
There are storm warnings across 10 northern provinces.
"We believe there has been a lot of damage," social welfare secretary Virginia Orogo said.
Workers clean up debris outside a mall that was damaged by strong winds from Typhoon Mangkhut across Cagayan province in the north east of the Philippines, 15-09-2018. Image: Aaron Favila/AP/Press Association Images
The state weather agency PAGASA has downgraded the threat level – but warned that storm surges and heavy rain could still cause widespread flooding and landslides.
"We are asking the people to remain alert and continue taking precautions," said meteorologist Rene Paciente.
Defence Secretary Delfin Lorenzana said Tuguegarao airport's terminal roof and windows had been shattered, with the wind flipping chairs and tables around inside.
It is the start of the rice and corn harvesting season in Cagayan province, where farmers have been scrambling to save what they can of their crops.
Residents collect coconuts which fell due to strong from Typhoon Mangkhut as it barrelled into Tuguegarao city in the north east of the Philippines, 15-09-2018. Image: Aaron Favila/AP/Press Association Images
The Philippines is no stranger to severe weather, where there are an average of 20 typhoons and storms each year.
Mangkhut is the 15th - and the strongest - storm this year.
It is heading towards Hong Kong, where Security Minister John Lee Ka-chiu warned residents it would be bringing "winds and rains of extraordinary speeds, scope and severity."
"Each department must have a sense of crisis, make a comprehensive assessment and plan, and prepare for the worst," he said.
Airline Cathay Pacific said it expected more than 400 flight cancellations over the next three days.