NEW: More than 800 people are injured
Chinese Premier Wen Jiabao visits the affected areas
Tens of thousands are evacuated
Communication lines and other infrastructure are downed
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 800 others were injured in the Friday quakes, according to Xinhua news agency. Officials fear the death toll may rise as they scramble to reach affected areas.
Large rocks blocked roads, and communication lines and other infrastructure were downed, hampering rescue efforts.
About 100,000 people have been evacuated and 100,000 others are in need of relocation, state media reported.
Premier Wen Jiabao inspected stricken areas early Saturday and visited the injured, the news agency reported. Wen will direct rescue operations.
Initial estimates put the “direct economic losses” from the tremors at more than half a billion dollars, the news agency said.
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.
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.