At least 21 people were killed when a powerful earthquake struck southwest China on Monday, state media reported, as violent tremors in a remote region damaged homes and left some areas without power.

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

According to state broadcaster CCTV, 14 people lost their lives in Sichuan’s Shimian District and seven died in nearby Luding District.

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 downstairs neighbors said they felt it very clearly,” said Chen, a Chengdu resident.

“But because Chengdu is currently under epidemic management, people are not allowed to leave their residential areas, so many of them rushed to their yards,” she added.

At least one town has suffered “severe damage” from landslides in the mountains triggered by the quake, CCTV reported.

A road to another town was blocked and telecommunications lines in areas with more than 10,000 residents were severed, the broadcaster said, adding that shocks also took down some power plants in the Garze and Ya’an areas.

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

Video posted online by the China Earthquake Networks Center showed boulders thundering down mountainsides in Luding County, kicking up clouds of dust as tremors rattled roadside telephone wires.

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

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

The authorities also sent thousands of tents, blankets and folding beds to the affected areas, according to the broadcaster.

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

A Chongqing resident said the quake was “quite noticeable” and shook the lights and furniture in his fifth-floor apartment.

“I was pretty scared,” he told AFP, “but it didn’t seem to worry people here.”

Earthquakes are fairly common in China, particularly in the seismically active southwest of the country.

An 8.0 magnitude tremor in Wenchuan County, Sichuan, in 2008 killed tens of thousands and caused extensive damage.

Two earthquakes in southwest China in June killed at least four people and injured dozens more.

This month, a shallow magnitude 6.1 shock hit a sparsely populated area about 100 kilometers west of Chengdu.

A second 4.5 magnitude quake followed three minutes later in a nearby county, killing and injuring.

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

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