* Fund operates under ethical guidelines set by parliament OSLO, March 10 (Reuters) - Norway’s $1.3 trillion wealth fund will probe whether companies it is invested in may be using the labour of ethnic Uighurs and other Muslims linked to China’s internment camp system in the country’s Xinjiang region, the head of the fund’s ethics watchdog told Reuters. The world’s largest sovereign wealth, which has massive market influence because it owns 1.5% of the world’s listed shares across 9,100 companies, operates under ethical guidelines set by parliament. Johan H. Andresen, chair of the fund’s Council on Ethics, said the fund had begun identifying companies that it said used workers that had been held in internment camps in Xinjiang.