China's largest oil producers have asked the National Development and Reform Commission for permission to hike retail prices of petrol and diesel, the South China Morning Post reported. Both China Petroleum & Chemical (Sinopec) and PetroChina want to boost prices to curb losses from the rising cost of crude oil. China has not raised prices since May 2006. The price of crude for delivery in August jumped 3% to US$72.81 a barrel on Friday, the highest price since August 15 last year. Price hikes are often driven by turmoil in oil-producing countries like Iran, Nigeria and Iraq. The newspaper cited UBS analysis that crude prices would average US$72 in the third quarter of this year and US$69 in the fourth. "For every barrel of imported oil (on current prices) we refine, our loss will increase by more than US$10," a Sinopec refinery official said.