More than 1800 people were reported injured with at least 12,000 homes destroyed and 30,000 damaged in the mountainous region in the south-west of the country.

President Xi Jinping said saving people's lives was the highest priority after the 6.5 magnitude earthquake, Yunnan's worst in 18 years, hit Zhaotong, north-east of the province's capital, Kunming.

Premier Li Keqiang , who was travelling to the disaster area, also urged local authorities to try everything possible to save those injured and buried in rubble, while emphasising the importance of maintaining social order in the quake zone.

More than 400 aftershocks, all measuring below 5 in magnitude, as well as heavy rain, hampered rescue efforts overnight.

The Zhaotong party secretary said there had been great difficulty in moving a large number of victims, because of blocked roads and a lack of resources.

The main road leading to the most heavily affected area was initially blocked by a landslide but had been cleared by late Sunday, according to the state news media.

The earthquake, which struck on Sunday at 4.30pm local time, was powerful enough to be felt in two neighbouring provinces, Chinese state broadcaster CCTV said.

Ma Liya, a resident of Zhaotong, told state news agency Xinhua that the streets there were like a “battlefield after bombardment.”

‘‘Too many buildings were damaged and we are collecting data on deaths and injuries,’’ Xinhua quoted local official Chen Guoyong as saying in the township of Longtoushan, which sits at the epicentre.

Zhang Fang, 20, a resident of Longtoushan, said she had been cooking potatoes in her family's mud-brick kitchen when the quake struck.

"I just fell to the ground and stayed there until the shaking stopped, and then I cried and cried," Ms Zhang said.

She said most of the buildings in her village were flattened, including an elementary school where a number of students were said to have been trapped.

State television broadcast footage of people running from homes and gathering in the streets, as witnesses described the devastation on social networks.

‘‘The walls of several buildings crumbled, and water pipes were ruptured. The electricity was cut off,’’ wrote a user in Ludian county, 23 kilometres from the epicentre, on China’s Twitter-like Weibo.

The user’s message was accompanied by images of cracked walls and a pile of bricks strewn across the road.

Ludian county was the worst hit, with 122 residents killed, more than 180 missing and 1300 injured.

At least another 53 deaths were recorded in neighbouring districts.

Electricity and telecommunications have been cut across the area.

Ludian, with a population of 265,900, is home to a mix of ethnic groups, including members of the Miao, Zhuang and Bai minorities. It is among the poorest regions in the country.

In September 2012, a 5.6-magnitude earthquake hit the same area, killing 81 people and injuring 821. In the 1970s, two strong earthquakes killed more than 15,000 people in the province.

In 1970, a magnitude-7.7 earthquake in Yunnan killed at least 15,000 people. In September 2012, 81 people died and 821 were injured in a series of quakes in the Yunnan region.

In 2008, the government was severely criticised for responding too slowly to a powerful earthquake in Sichuan province that killed more than 70,000 people. When a series of earthquakes hit Gansu province in north-western China in 2013, Chinese officials and government organisations rushed to the affected area to offer assistance and comfort.

The 2008 earthquake also raised the issue of the substandard construction of many schools and other buildings that collapsed.

The government is sending 2000 tents, 3000 folding beds, 3000 quilts and 3000 coats to the disaster zone, where heavy rain forecast for the coming days will add to the misery, Xinhua said.

With agencies