Heraldo de Madrid - Strong earthquake in southwest China kills 21

The magnitude 6.6 quake hit about 43 kilometres (26 miles) southeast of the city of Kangding in Sichuan province at a depth of 10 kilometres, according to the US Geological Survey.

Fourteen people lost their lives in Sichuan's Shimian county and seven died in nearby Luding county, according to state broadcaster CCTV.

Tremors shook buildings in the provincial capital of Chengdu -- where millions are confined to their homes under a strict Covid lockdown -- and in the nearby megacity of Chongqing, local residents told AFP.

"I felt it quite strongly. Some of my neighbours on the ground floor said they felt it very noticeably," said Chen, a resident of Chengdu.

"But because Chengdu is currently under epidemic management, people aren't allowed to leave their residential compounds, so many of them rushed out into their courtyards," she added.

At least one town had suffered "severe damage" from mountain landslides triggered by the quake, CCTV reported.

A road to another town was blocked and telecommunications lines in areas home to more than 10,000 people were severed, the broadcaster said, adding that shocks also forced some power stations offline in the areas of Garze and Ya'an.

Footage broadcast by CCTV appeared to show damaged buildings and a street strewn with fallen masonry in Garze.

A video posted online by the China Earthquake Networks Center showed boulders thundering down mountainsides in Luding county, kicking up clouds of dust as tremors swayed roadside telephone wires.

State media reported that several aftershocks were recorded in nearby areas. A smaller magnitude 4.6 tremor hit eastern Tibet less than an hour after the initial quake, according to the USGS.

Hundreds of rescue workers were dispatched to the epicentre, CCTV reported, alongside footage of firefighters in orange jumpsuits boarding trucks and navigating a highway littered with rocks and other debris.

Authorities also sent thousands of tents, blankets and foldable beds to the affected areas, according to the broadcaster.

Other state media photos showed officials in military fatigues heaving shovels and other equipment along a highway -- all while wearing face masks as a Covid precaution.

A resident of Chongqing said the quake was "pretty noticeable" and that it had shaken the lights and furniture in his fifth-floor apartment.

"I was pretty scared," he told AFP, "but it didn't seem to faze people here."

- Summer of extremes -

Earthquakes are fairly common in China, especially in the country's seismically active southwest.

A magnitude 8.0 quake in 2008 in Sichuan's Wenchuan county left tens of thousands dead and caused enormous damage.

At least four people were killed and dozens more injured after two earthquakes in southwestern China in June.

That month a shallow 6.1-magnitude shock hit a sparsely populated area about 100 kilometres west of Chengdu.

It was followed three minutes later by a second quake of magnitude 4.5 in a nearby county, where the deaths and injuries occurred.

Authorities in Chengdu extended the city's lockdown on Sunday as they fight a Covid flare-up with hundreds of cases.

The region has also suffered a summer of extreme weather, with a record-breaking heatwave noticeably drying rivers in Chongqing.

C.Valero--HdM