Typhoon Mangkhut has reached China after leaving at least 40 people dead in its wake across the northern Philippines.
It is feared the death toll may rise as blocked roads and communication failures mean many rural areas have still not been reached.
Nearly half a million people have been evacuated in seven cities ahead of the storm’s landfall in China’s Guangdong province.
China’s national meteorological centre has warned that southern China "will face a severe test caused by wind and rain" and urged officials to prepare for possible disasters.
A tree uprooted by Typhoon Mangkhut in Hong Kong, 16-09-2018. Image: Lo Ping Fai/Xinhua News Agency/PA Images
The Typhoon is the strongest weather system the world has seen this year carrying wind gusts reaching 305kph.
Its strength equalled that of an Atlantic category 5 hurricane when it made landfall in the Philippines on Saturday.
It has whipped up torrential rains in southern China and Hong Kong – after leaving a trail of destruction in its wake across the northern Philippines.
The gambling enclave of Macau has closed down all 42 of its casinos for the first time in anticipation of the storm.
Trees in the wind on the Hong Kong coast, 17-09-2018. Image: Vincent Yu/AP/Press Association Images
Meanwhile, the Hong Kong Observatory warned people to stay away from the Victoria Harbour landmark, where storm surges battered the waterfront.
Surges of nearly 10ft are expected across the shoreline.
Hong Kong's security minister John Lee Ka-chiu urged residents to prepare for the worst.
"Because Mangkhut will bring winds and rains of extraordinary speeds, scope and severity, our preparation and response efforts will be greater than in the past,” he said.
"Each department must have a sense of crisis, make a comprehensive assessment and plan, and prepare for the worst."
Workers transfer sacks of grains from a toppled truck in Cagayan province, northeastern Philippines on Sunday, 16-09-2018. Image: Aaron Favila/AP/Press Association Images
In the Philippines, houses collapsed as more than five million people found themselves in the path of the deadly typhoon.
Francis Tolentino, an adviser to President Rodrigo Duterte, said most of the fatalities happened in landslides in mountainous areas.
Twenty deaths in the Cordillera region in Luzon and four in nearby Nueva Vizcaya province were caused by landslides.
Mr Tolentino said another death resulted from a tree falling in the province of Ilocos Sur.
Three more deaths have been reported in northeastern Cagayan province, where the typhoon made landfall.
Two toddlers died with their parents who had refused to immediately evacuate from their high-risk community in a mountain town in Nueva Vizcaya province, authorities said.
A family shares a meal at a temporary evacuation centre as electricity was shut-off after the onslaught of Typhoon Mangkhut in Cagayan province, northeastern Philippines, 15-09-2018. Image: Aaron Favila/AP/Press Association Images
About 87,000 people had been evacuated from high-risk areas of the Philippines.
They were advised not to return home until the lingering danger had passed.
China and the Philippines agreed to postpone a visit by Chinese foreign minister Wang Yi that was to start on Sunday, due to the typhoon's onslaught.
The storm caused nearly 150 flights, a third of them international, to be cancelled and sea travel to be halted.
The Hong Kong Observatory said that although Mangkhut had weakened slightly, its extensive, intense rain bands were bringing heavy downfall and frequent squalls.