BEIJING, China -- The death toll from a landslide triggered by heavy rains in northern China has risen sharply to at least 21, authorities said on Sunday, with six others missing.

China has faced deadly floods and historic rainfall in recent weeks, with dozens killed in storms in the northern part of the country.

"Twenty-one people were found dead so far, and six others are still missing," the Xi'an emergency management bureau said in an online statement about the landslide on Sunday.

State media had put the toll at four earlier on Sunday.

A mountain flash flood in the village of Weiziping, south of Xi'an in Shaanxi province, caused a landslide on Friday that swept away two houses and damaged roads, bridges, electricity supply and other infrastructure, national public radio CNR reported earlier.

A hundred soldiers as well as firefighters were mobilised for the relief operations "which are continuing" on Sunday, according to CNR.

CNR broadcast images on Weibo showing rescuers clearing rocks and trees from the edge of a river and carrying victims on stretchers.

According to the Xi'an emergency management bureau statement, more than 980 people were mobilised for the rescue effort, using life detectors and search dogs.

The landslide "destroyed" two houses and caused power cuts in 900 homes, it said.

"According to experts, the cause of the disaster is a flash flood mud-rock flow caused by short-term torrential rain," the statement said.

"Up to now, a total of 186 people have been relocated and resettled... 49 communication base stations in the disaster-stricken area have resumed service, and power supplies have been resumed in 855 homes."

- Record-breaking rains -

The recent record-breaking downpours followed weeks of historic heat, with scientists saying such extreme weather events are being exacerbated by climate change.

State media reported on Friday that 29 people died from flooding in Hebei province after Storm Doksuri -- which hit mainland China as a typhoon in late July -- brought on the most severe rainfall since records began 140 years ago.

Hebei province party chief Ni Yuefeng said during a visit to affected communities last week that the area could "reduce the pressure on Beijing's flood control" and serve as a "moat" for the capital.

At least 33 people have died in Beijing, including two rescue workers, authorities said this week.

And more than a dozen people were killed in northeastern Jilin province after torrential rain last week.

In neighbouring Liaoning province, two deaths were reported after the first few days of intense rain in late July.

At least seven people died in a flash flood southwest of Sichuan's capital Chengdu this week after an unexpected tide of water washed away a number of tourists on the Longxi River.

And in Gansu, five people were killed when they were swept away by mountain torrents after a rainstorm alert on Thursday, Xinhua said.