BEIJING - The China Iron and Steel Association (CISA) has protested at a markup by a leading iron ore producer that targets Chinese buyers.

"It is obviously unfair," a CISA official said on Friday, who did not name the company but hinted it is among the world's top-three iron ore miners.

When discussing new agreements with Chinese steel firms, the company decided to impose a premium in addition to prices published by Platts, a benchmark price assessment in physical energy markets, the official said.

The official said the practice damaged the current pricing mechanism and disturbed trade order, and called on the two sides to "sit down and talk" to solve the problem together.

China is the world's biggest consumer of iron ore, with the imports up 8.9 percent year on year in the first ten months.