At least 67 people were killed and 731 injured when two earthquakes struck a remote and mountainous area of southwest China on Friday, toppling houses and sending panicked crowds onto the streets. Residents described how people ran out of buildings screaming as the two shallow quakes hit on the border of Yunnan and Guizhou provinces an hour apart around the middle of the day. They were followed by a string of aftershocks. Television footage showed roads strewn with fallen bricks and rocks in Yunnan province\'s Yiliang county, which appeared to be worst hit. Authorities were sending thousands of tents, quilts and coats, and Premier Wen Jiabao was also heading to the area, the state Xinhua news agency said, confirming the death and injured toll, which rose steadily throughout the day. Footage on state television network CCTV showed hundreds of people crowded into a sports field in Yiliang. People took cover outside after the first quake and did not return indoors, said a man surnamed Xia reached by phone. \"Lots of people are outside because they fear aftershocks,\" he said. \"I was walking on the street when I suddenly felt the ground shaking beneath me,\" posted one witness on Sina Weibo, a microblog similar to Twitter. \"People started rushing outside screaming, it still scares me to think of it now.\" The US Geological Survey said the first quake struck at 11.20 am (0320 GMT) at a depth of around 10 kilometres (six miles), with the second quake around an hour later, putting the magnitude of both at 5.6. The earthquakes cut off electricity and triggered landslides, blocking roads, which was complicating the rescue mission, Xinhua said. Li Fuchun, the head Luozehe township, identified as the epicentre, told Xinhua: \"Roads are blocked and rescuers have to climb mountains to reach hard-hit villagers.\" Peng Zhuwen, a worker at a zinc mine in Luozehe, added: \"It is scary. My brother was killed by falling rocks. The aftershocks have struck again and again. We are so scared.\" Yunnan\'s civil affairs department said that 6,650 houses had been destroyed and 100,000 people evacuated. There were also fears of disease after thousands of cattle were killed when sheds caved in. The death toll could still rise because a few villages remain blocked by landslides, Xinhua said, quoting a seismologist as saying that the hardest-hit areas are relatively populous and poor, meaning buildings collapsed easily. Rocks as tall as four metres (13 feet) crashed into mountain roads, crushing houses and cars, the report said. Southwest China is prone to earthquakes. In May 2008, an 8.0-magnitude quake rocked Sichuan and parts of neighbouring Shaanxi and Gansu provinces, killing tens of thousands and flattening swathes of the province. Local hospitals and government officials could not be reached for comment.