BEIJING (Reuters) - China expresses regret at a U.S. challenge to its raw materials export duties and will handle the issue according to the World Trade Organization (WTO) dispute resolution procedures.

The remarks made by the commerce ministry came after the United States launched a challenge against China's export duties on nine key metals and minerals on Wednesday, arguing that they violate WTO rules and give an unfair advantage to Chinese manufacturers.

The ministry also said in the online statement that export tariffs are part of efforts to improve environmental protection.

(Reporting By Beijing Monitoring Desk)