Chinese aluminum foil producer Shantou Wanshun Package Material Stock Co on Monday said its subsidiary is suing the US over twin anti-dumping and anti-subsidy duties Washington imposed on its shipments.

In a statement to the Shenzhen Stock Exchange, Wanshun said Jiangsu Zhongji Lamination Materials, which was hit with a countervailing duty of 17.14 percent and an anti-dumping duty of 37.99 percent earlier this year, had filed a lawsuit with the US Court of International Trade.

Zhongji was among the Chinese foil companies that unsuccessfully filed a joint “no injury” claim with the US International Trade Commission last year as Washington probed whether the companies were unfairly subsidized, and is now trying to reverse the duties on its own.

The total duties of 55.13 percent on Zhongji’s foil were the lowest imposed on Chinese foil makers, Wanshun’s Board Secretary Huang Wei told Reuters. This shows the US side had taken some of its arguments into account, she said.

“But there are still some unreasonable elements inside” the ruling, she added.

Huang pointed to the US comparing the prices of China’s aluminum foil exports to South Africa as a reference case. The stock exchange filing noted that Bulgaria would have been a more appropriate choice.

The document made no mention of damages being sought but Huang said she hoped the US would remove the twin duties.

Aluminum has been a focal point of the US-China trade row, with Washington calling on China, the world’s top producer of the metal, to rein in excess production capacity.

US President Donald Trump imposed a broad 10-percent import duty on aluminum imports from China and other countries from March 23.

“We will still export to the US,” Huang said. Even after the double duties, “our customers still came back to buy” because of favorable pricing, she added.

A search of the US Court of International Trade website showed Jiangsu Zhongji had filed a case against the US in June but the full document was unavailable.

Associated defendants named in the stock exchange filing were the Aluminum Association Trade Enforcement Working Group and its individual members, as well as JW Aluminum Co, Novelis Corp and Reynolds Consumer Products.

The US Aluminum Association, which had previously hailed the twin tariffs as a victory for US foil producers and rules-based trade, said it was confident the duties would be upheld.

“We will work vigorously, along with the individual member companies that participated in the investigation, to defend the government’s unanimous finding that US industry has been materially injured by unfairly-traded imports of certain aluminum foil from China,” a spokesman said in a statement.

The other parties could not immediately be reached for comment outside of business hours in the US.