Media playback is unsupported on your device Media caption Rain in Beijing: "Worst in 60 years"

The heaviest rainfall to hit China's capital Beijing in 60 years has left 37 people dead and stranded thousands at the main airport.

The deluge struck on Saturday afternoon and continued into the night, flooding major roads, state media said.

Roof collapses, lightning strikes and electrocution from downed power lines were among the causes of the deaths.

More than 500 flights were cancelled at the main airport, the Beijing News reported.

The floods also caused a backlash on the internet, with many angry at the lack of warning and the apparent inadequacy of drainage systems.

State news agency Xinhua said 460mm (18.1 in) fell in Beijing's Fangshan district, with the capital as a whole averaging 170mm.

I was terrified by the thought of tumbling down a manhole without a cover Reece Ayers, Beijing resident Resident describes Beijing deluge

About 1.9m people had been affected by the downpour, and flood and economic losses had been estimated at 10bn yuan ($1.5bn, £960m), Pan Anjun, deputy chief of Beijing flood control headquarters, was quoted as saying by Xinhua news agency.

By Sunday evening, more than 65,000 people had to be evacuated. Beijing officials said 37 people had died, 25 of them from drowning.

Outside the capital, 17 people were reportedly missing in northwestern Shaanxi province and eight people dead in southwestern Sichuan province due to heavy rains, said another Xinhua report.

Authorities in Shaanxi's Fugu county said four bodies had been found, but it was not known if they were among the 17 missing, Xinhua said.

'Like a waterfall'

British student Tom Smith, who has been living in China for a year, told the BBC the storm in Beijing was like "standing under a waterfall.

"All the manholes had vanished because the water was sitting on top of them. It looked very dangerous and very difficult to find where these holes were," he said.

Image caption Chaos at the capital's Guangqumen overpass

British businessman Ewen Wardman saw a woman narrowly escape death after being trapped by the floods in the manhole drainage system.

"I saw a woman walking across a road. All of a sudden she was swept 100 metres down the road and came to an abrupt halt, stuck in the road with water flowing over the top of her.

"Some 20-30 people had surrounded her but only a few could help," he told the BBC. "It didn't look good at first as the water continued to flow over her head, but after about five minutes they pulled her free."

Many Chinese newspapers criticised the capital's drainage system for failing to cope with the rain storm, in contrast to the centuries-old ditches around the Forbidden City that kept the national monument relatively dry.

Hundred of thousands of people also left comments on weibo platforms - China's equivalent of Twitter.

A Tencent Weibo user from Shandong asked how, as an Olympic city, Beijing's drainage system could be so vulnerable. On Sina Weibo, a user from Shaanxi urged people to learn how to swim, calling the government was "unreliable".

"Wishing you happy-ever-after in the afterlife, let's hope at least it has better drainage," sad a Sina Weibo user from Jiangsu.

Other users blamed "sub-standard" weather forecasting and warning services.

But a report in the Global Times newspaper said people in Beijing were also offering help to those affected or stranded by the rain via social media.

Rides, meals and accommodation were among the offers of assistance posted on weibo.