MENTOUGOU: At least 11 people are dead and 27 missing after heavy rains lashed Beijing, state media said Tuesday, in downpours that have submerged roads and deluged neighbourhoods with mud.

Storm Doksuri, a former super typhoon, had swept northwards through China since hitting southern Fujian province on Friday after first scything through the Philippines.

Heavy rains began pummelling Beijing and its surrounding areas on Saturday, with nearly the average rainfall for the entire month of July dumped on the capital in just 40 hours.

Swathes of suburban Beijing remain badly hit by the rains -- some of the city's heaviest in years.

On Tuesday, state broadcaster CCTV reported the rains had killed at least 11 people and that 27 were missing.

Among the dead were two workers "killed on duty during rescue and relief" efforts, it said.

More than 100,000 people across the city deemed at risk had been evacuated, state-owned tabloid the Global Times reported.

On the banks of the Mentougou river, one of the areas worst affected by the flooding, AFP reporters saw muddy debris strewn across the road.

One local elderly man told AFP he had not seen flooding this bad since July 2012, when 79 people were killed and tens of thousands evacuated.

"This time it's much bigger than that," he said, declining to give his name.

"It's a natural disaster, there's nothing you can do," a man in his 20s surnamed Qi told AFP as he waited for a taxi outside a hospital with his grandmother.

"(We) still have to work hard and rebuild," he added.

About a dozen emergency vehicles, including trucks with water tanks and bulldozers, were spotted on the road between Shijingshan and Mentougou districts.

Parts of the road were still closed off and workers in bright orange raincoats used shovels to clear the road.

Chaotic scenes 

President Xi Jinping on Tuesday called for "every effort" to rescue those "lost or trapped" by the rains.

Local authorities "must do a good job in treating the injured and comforting the families of victims, and minimize casualties", CCTV quoted Xi as saying.

"They must properly relocate affected people, work quickly to repair damaged transportation, communication and electricity infrastructure, and restore the order of normal production and life as soon as possible," he added.

"Xi Jinping emphasised that it is currently the critical period for flood control in late July and early August," state media said.

Live images from broadcaster CCTV on Tuesday morning showed a row of buses half submerged in floodwater in Beijing's southwest Fangshan neighbourhood.

Around 150,000 households in Mentougou were without running water, the local Communist Party newspaper Beijing Daily said, with 45 water tankers dispatched to offer emergency supplies.

Local media on Monday published footage of chaotic scenes aboard high-speed rail trains stranded on tracks for as long as 30 hours, with passengers complaining they had run out of food and water.

Parts of neighbouring Hebei province remain under red alert for rainstorms, with authorities warning of potential flash floods and landslides.

The city activated a flood control reservoir on Monday for the first time since it was built in 1998, the Beijing Daily said.

And in Handan, Hebei province, rescuers lifted by crane reached a man trapped atop his car by floodwaters, lifting him to safety before the vehicle was flipped over and washed away by the current.

China has been experiencing extreme weather and posting record temperatures this summer, events that scientists say are being exacerbated by climate change.

The country is already preparing for the arrival of another typhoon -- Khanun, the sixth such storm of the year -- as it nears China's east coast.