Beijing (CNN) -- The death toll may climb after a series of earthquakes in southwestern China killed at least 80 people and injured 731, a state-run news agency reported Saturday.
More than 6,600 homes were destroyed and about 430,000 damaged in Friday's quakes, Xinhua said.
Premier Wen Jiabao inspected stricken areas early Saturday and visited the injured, the news agency reported. Wen will direct rescue operations.
President Hu Jintao called for immediate relief efforts, according to China Central Television.
Xinhua reported that 100,000 people have been evacuated and another 100,000 are in need of relocation.
Initial estimates put the "direct economic losses" from the tremors at more than half a billion dollars, the news agency said.
Xinhua described the mountainous area hit hard by the quakes as poverty-stricken. It said telecommunications and traffic infrastructure were seriously damaged.
Four earthquakes struck near the border of the provinces of Yunnan and Guizhou between 11:19 a.m. and 1:12 p.m. local time, the U.S. Geological Survey said. Their magnitudes ranged between 4.8 and 5.6, according to the U.S. agency.
The first quake took place near the border between Yiliang County in Yunnan and Weining County in Guizhou, Xinhua said.
All four quakes struck at a depth of about 10 kilometers (six miles), the USGS said.
The southwestern region of China is prone to earthquakes. In May 2008, a magnitude 7.9 quake in Sichuan province caused widespread devastation, killing at least 69,000 people.
CNN's Steven Jiang contributed to this report.