BEIJING—An earthquake that hit southwest China's Sichuan and Yunnan provinces has killed 25 people, damaged or destroyed more than 100,000 homes and affected at least 440,000 residents, state media said on Sunday.

The epicenter of Saturday's quake, which struck around 4:30 p.m. (3:30 a.m. EDT), was about 20 miles southeast of Panzhihua, near Sichuan's border with Yunnan, according to the U.S. Geological Survey. The quake was about 6 miles deep.

The U.S. Geological Survey put the magnitude of the quake at 5.7, while China's official state media Xinhua news agency said it measured 6.1.

Xinhua said the quake had injured 192 people, and three more were missing.

It added that 656 schools had also been damaged and that heavy rain and difficult terrain were hampering rescue efforts, with mobile telephone communications patchy.

State television showed pictures of houses with large cracks in their sides and broken tiles on the road.

Parts of Sichuan province were devastated by an earthquake that killed about 70,000 people in May. The province, known for its pandas and fiery cuisine, has struggled to rebuild after the disaster, which left 10 million people homeless.