U.S. trade officials reacted icily to China’s decision to challenge U.S. shrimp duties at the World Trade Organization, which they said would complicate efforts to resolve a trade spat involving a number of other U.S. trading partners.

“The United States is deeply disappointed in China’s decision to request consultations,” Nefeterius McPherson, a spokeswoman for the U.S. Trade Representative’s office, said in a statement.

“The decision now by China to pursue new claims against the United States on ‘zeroing’ only complicates resolution of this issue,” she said, referring to a controversial U.S. method of calculating anti-dumping duties.

A request for consultations is the first step in resolving a trade spat within the WTO. If the two sides cannot reach agreement on the issue in the next 60 days, Beijing could ask for a dispute settlement panel to hear its complaint.

The United States, like many countries, imposes anti-dumping duties on goods it determines are sold in its market at less than fair value.

That involves making price comparisons to estimate the amount of dumping that has occurred.

In zeroing, examples where imported goods cost more than they do in their home market are ignored, which critics says unfairly inflates the size of antidumping duties.

The United States has reduced its use of zeroing in response to repeated WTO rulings, and in December proposed to end it in annual reviews of anti-dumping duties.

“Nonetheless, China has determined to pursue consultations even as the United States is in the midst of its domestic legal and administrative compliance process, including consultations with Congress,” McPherson said.

The United States first imposed anti-dumping duties on shrimp from China, Brazil, India, Thailand and Vietnam in 2005 and has been considering the larger question of whether to extend them for another five years.

U.S. Gulf shrimpers, still reeling from last year’s massive BP oil spill and earlier devastating hurricanes, haver urged the U.S. International Trade Commission to continue the duties. The trade panel will vote next month on the issue. (Reuters)