U.S. trade officials have objected to the European Union's request to impose up to $311 million in annual sanctions on U.S. goods in a long-running dispute over a method for calculating anti-dumping duties, a U.S. trade official.

"On February 12th, the United States filed its objection," USTR spokeswoman Nefeterius McPherson told Reuters in an email. "The filing of the objection automatically resulted in the matter being referred to arbitration. The objection should be on the WTO website by tomorrow."

The EU notified the World Trade Organization earlier this month that it wanted to impose the sanctions after the United States failed to comply with an original decision in a case launched by Brussels in 2003 over anti-dumping duties on steel products and other goods.

The EU has proposed imposing a prohibitive import tariff of 100 percent on U.S. exports worth $311 million, or a tariff of 13.8 percent on exports worth $477 million, and reserved the right to impose further sanctions related to a practice called zeroing.

The WTO's dispute settlement body is expected to take up the EU sanctions request on Thursday. The U.S. objection starts an arbitration process that usually takes about two months to decide the amount of sanctions the EU can impose.

WTO rules allow members to slap extra duties on goods sold at below-market or "dumped" prices if that hurts businesses in the importing country.

Calculating the anti-dumping duties typically involves comparisons of the prices of different batches of imported goods to work out the average difference in price.

The dispute with the EU focuses on Washington's "zeroing" method for calculating the duties, which has been found by WTO judges to be a violation of global trade rules.

The practice essentially ignores -- or treats as zero -- sales where the imported goods are priced higher in the United States than they are in their home market, which critics say unfairly inflates the duty.

The United States has said it intends to comply with the adverse ruling on zeroing. But it also complains WTO panel have gone beyond the bounds of agreed-upon global trade rules in striking down the practice. (Reuters)