Beijing (AFP) - Five factory workers were killed when a building collapsed during a powerful earthquake that rocked northwestern China, state media said on Tuesday. The deaths were the first reported so far from the 6.5-magnitude earthquake that hit Qinghai province on Monday, about 150 kilometres (93 miles) northeast of the city of Golmud. The quake shook buildings hundreds of kilometres away and sent people fleeing into the streets. The five workers died in the provincial capital of Xining, 615 kilometres from the epicentre, when a workshop they were building collapsed, Xinhua news agency said. One other victim was hospitalised in critical condition, it added. The quake hit at 9:22 am (0122 GMT) in a sparsely populated area of the rugged province, the US Geological Survey said. It reported that a 5.0-magnitude aftershock rattled the region two and a half hours later. China suffers frequent earthquakes. An 8.0-magnitude quake which hit the southwestern province of Sichuan on May 12 flattened entire towns and left up to 88,000 people dead or missing.