Beijing - The casualty toll has risen to at least 33 dead and 506 injured after an earthquake on the borders of China's south-western provinces of Sichuan and Yunnan, the government said Monday.

Most of the casualties were in Sichuan's worst-hit county of Huili, where 22 people were reported dead after Saturday's 6.1-magnitude quake, the State Seismological Bureau said on its website.

State media said local authorities distributed some 10,000 tents in three badly affected areas, where some 180,000 buildings collapsed and at least 40,000 people were evacuated.

Five people were reported dead in Sichuan's Panzhihua city and at least six died in Yunnan province, reports said.

The quake affected some 800,000 people and was felt in both provincial capitals, prompting many people to remain outdoors on Saturday evening for fear of aftershocks.

Electricity, roads and communications were cut off by earthquake damage in several rural areas of Yunnan and Sichuan.

Relief and rescue efforts were hampered by rain and a 5.6-magnitude aftershock on Sunday afternoon.

Sichuan was hit by a devastating earthquake that killed at least 70,000 people on May 12, with nearly 20,000 people still listed as missing.

Thousands of aftershocks have shaken Sichuan since the 8.0-magnitude quake in May along the Longshan geological fault.

The quakes on Saturday and Sunday were at the southern end of the Longshan fault. (dpa)