China Mineral Resources Group Co. (CMRG) has widened restrictions affecting iron ore from Australian producer Fortescue Ltd. ASX:FMG, extending them beyond port inventories to cover fresh purchases of the company's Super Special Fines product, Bloomberg News reported on Friday, citing people familiar with the matter.

The state-backed buyer has also instructed a number of Chinese steelmakers and trading firms to refrain from purchasing new U.S. dollar-priced cargoes of Fortescue's Super Special Fines., the report said.

Reuters was not able to independently confirm the Bloomberg report.

Earlier this week, CMRG verbally informed some domestic steel mills that, from July 15, they must not take delivery of Fortescue's Super Special Fines and Fortune Fines held at Chinese ports. The move was the latest sign of Beijing's efforts to tighten its influence over the iron ore market and increase control over pricing.