A sniffer dog lies on the ground as rescuers take break from rescue efforts in Ninglang county, Southwest China's Yunnan province, June 25, 2012. [Photo/Asianewsphoto]

KUNMING - At least four people have been killed and over 100 others injured after an earthquake hit a mountainous area in southwest China on Sunday, local authorities said on Monday.

The magnitude-5.7 quake, which struck the border of Yunnan and Sichuan provinces at 3:59 p.m., killed three people in Ninglang county of Yunnan and another one in Sichuan's Yanyuan county.

On Sunday, the earthquake was followed by 53 aftershocks and the strongest one was measured at magnitude 3.8, said Chen Qin, deputy head of the Yunnan provincial seismology bureau.

As of 2 a.m., 106 people, including seven tourists, have been found injured in Ninglang, where the quake was strongly felt and many Yi ethnic minority live. Twenty of them suffered severe wounds, said He Lianghui, mayor of Lijiang city, which administers Ninglang.

The quake toppled over 4,280 houses and cut roads and water supplies in the county, disrupting the lives of more than 21,800 people, said He.

It also killed more than 1,200 domestic animals, He said.

A quake relief headquarters has been set up and a team of 1,300 rescuers have been dispatched to the quake-hit region, according to the city government.

Provincial and city authorities had sent relief supplies, including tents, coats, quilts, bottled water and food to Ninglang.

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Rescuers clear the rubble among destroyed homes after earthquake in Ninglang county, Southwest China's Yunnan province, June 25, 2012. [Photo/Asianewsphoto]