At least 67 people were killed and hundreds injured as a strong earthquake of 7.1 magnitude struck northwest China's remote Qinghai province on early Wednesday, state media reported.<br/><br/>The quake hit the Yushu County in Yushu prefecture with a depth of about 33 km, causing casualties and collapsing some homes, Xinhua news agency reported. <br/><br/>Three aftershocks rattled the area near the border with Tibet within a half-hour after the quake, with magnitudes of 5.3, 5.2 and 4.7 on Richter scale. <br/><br/>Several people were reported buried under the debris of the buildings.<br/>