At least 12 people have been killed and one missing after Typhoon Hato swept through southern China and the territory of Macau, leaving many millions of dollars worth of destruction.

At least eight were killed in Macau, according to AFP news agency. The Macau government said that 153 were also injured in the gambling enclave.

China's official Xinhua News Agency said on Wednesday another four were killed in the neighbouring province of Guangdong.

Local media and social media showed severe flooding had left cars underwater and people swimming in Macau's city streets, with the territory's mega-casinos running on backup generators.

A 30-year old man in Macau was reportedly hit by a wall that collapsed in the strong winds, according to the Macau government.

A man and a woman also reportedly drowned in an underground car park, while a Chinese tourist was killed in a hit-and-run incident during the typhoon.

Typhoon Hato has hit HK/Macau pic.twitter.com/cbXsc731uf — Simon Thum (@SimonThum) August 23, 2017

Apple Daily news website showed footage of people swimming through muddy water in what are usually roads, and being swept off their feet by winds.

Macau's sprawling Venetian casino resort was on backup power, and without airconditioning or proper lighting, a source told AFP.

One employee of Sands, which owns the Venetian and the Parisian, said power had been out across the whole of Macau but was beginning to return.

"All transportations - air, ground, sea - have halted, so customers who have checked out cannot leave yet."

Residents took to social media to complain about city-wide power and mobile phone network outages.

At least 50 flights in Macau were also cancelled. By evening, parts of Macau were still without power.

Destruction in Hong Kong

Hurricane-strength winds and heavy rain had earlier hit Hong Kong, leaving more than 80 injured.

One 83-year-old man earlier thought to be a victim of the weather committed suicide during the typhoon.

Hato sent metres-high waves crashing into Hong Kong's shorelines with flooding knee deep in some areas.

The typhoon shut down the stock market and forced the cancellation of hundreds of flights in the worst storm the city has seen for five years.

Meteorologists raised Hong Kong's most severe Typhoon 10 warning as the storm hit, only the third time in the past 20 years.

The South China Morning Post reported that damages, as well as the loss to Hong Kong's economy, could go as high as $1.02bn.

The typhoon passed as close as 60km and made landfall at 04:00 GMT in the southern mainland Chinese city of Zhuhai.

Thousands of people were evacuated on Tuesday in parts of southern China in preparation for the typhoon's arrival, the official Xinhua news agency said.

Swaths of marine rubbish washed up on beaches and in coastal residential areas, including white globs of palm oil which have been coming ashore since a massive spillage at sea earlier this month.

Gusts of up to 207 kilometres per hour brought flying debris, tearing down trees and scaffolding and smashing skyscraper windows.

Fallen trees cut off roads to parts of the territory.

Hato also reportedly brought as much as 400mm of rainfall.

More than 400 flights were cancelled, with flag carrier Cathay Pacific axing most of its departures until 09:00 GMT.

As of 13:00 GMT, the storm signal had been downgraded from 10 to 1 in the city.

Hong Kong is regularly besieged by typhoons between July and October, but direct hits are rare.

The city saw its strongest storm in 1962 when the eye of typhoon Wanda passed over it and gusts of 284 kilometres per hour were recorded.

It killed 130 people and destroyed thousands of residential huts, leaving 72,000 people homeless.

Al Jazeera's weather presenter Rob McElwee reported that Typhoon Hato is now heading to mainland China, and is expected to bring heavy rains in the next to days.