WASHINGTON, Oct. 13 -- The United States has requested the establishment of a dispute settlement panel at the World Trade Organization (WTO) to examine China's export restraints on 11 raw materials, the Office of the U.S. Trade Representative (USTR) said Thursday.

The United States had held consultations with China over the matter from Sept. 8 to 9, but the two sides did not resolve the dispute, the USTR's Office said, adding requesting a panel is the next step in the WTO dispute settlement process.

The WTO Dispute Settlement Body will consider the U.S. panel request at its meeting scheduled for Oct. 26, the office said.

The United States claimed that China's export restraints, including duties and quotas, on antimony, copper and other nine raw materials "provide an unfair competitive advantage to Chinese industry at the expense of manufacturers and workers in the United States."

But China's Ministry of Commerce has insisted that the duty and quota requirements on the export of 11 raw materials are imposed to protect the country's resources and the environment, and that they conform to WTO rules.

The U.S. challenges on China on raw materials come at a time of increasing anti-trade rhetoric in the current U.S. presidential campaign.

The Obama administration wants to demonstrate a tough stance on enforcing trade agreements in an attempt to draw support from lawmakers to ratify the Trans-Pacific Partnership trade agreement, a top legislative priority for President Barack Obama this year.

But U.S. House Speaker Paul Ryan has recently said that the TPP agreement does not have enough votes to pass the Congress this year, noting the Obama administration has to makes changes to the agreement to get congressional approval.