At least seven people were killed and 20 injured in an earthquake that jolted Southwest China's Yunnan and Guizhou provinces Friday, government sources said.

The 5.7 magnitude earthquake hit the border area of Yiliang County of Yunnan and Weining county of Guizhou at 11:19 am and the depth of its epicenter was about 14 km at 27.5 degrees north latitude and 104.0 degrees east longitude.

All the victims were from Yiliang County. In the meantime, more than 20,000 houses were damaged or had collapsed in the quake, according to the Yunnan provincial civil affairs department.

The epicenter was about 15 kilometers from the county seat of Yiliang. As of 1 pm, the area had been stricken by 16 aftershocks, with the strongest one measuring at magnitude-5.6, according to the provincial seismological bureau.

The province has already sent work teams to the quake-hit area and the civil affairs department is transporting thousands of tents, quilts and coats to the area.

So far, no casualties have been reported in Guizhou Province, but the quake has also damaged or even toppled homes in Weining county, said Chen Bo, head of the county government.