BEIJING - China will raise the retail prices of gasoline and diesel from Friday, the country's top economic planner said on Thursday.

The prices of gasoline and diesel will both increase by 110 yuan ($17.33) per ton in the seventh consecutive upward adjustment since the end of last year, according to the National Development and Reform Commission.

Under the current pricing mechanism, when international crude oil prices change by more than 50 yuan per ton and remain at that level for 10 working days, the prices of refined oil products such as gasoline and diesel in China are adjusted accordingly.

China's three biggest oil companies -- China National Petroleum Corporation, China Petroleum & Chemical Corporation, and China National Offshore Oil Corporation -- have been asked to maintain oil production and facilitate transportation to ensure stable supplies.