"We want reciprocity," said Pedro Ojeda, a lawyer for Canacar. "The U.S. has notoriously not kept its commitments." Mr. Ojeda said the complaint is the largest such demand made under Nafta, as the 1993 pact is known.

Deborah Mesloh, a spokeswoman for U.S. Trade Representative Ron Kirk, said Monday that, "We take our trade obligations very seriously and this is an issue we've been working on for a couple months." A State Department spokesman said the claim is "being studied."

The arbitration demand is the latest fallout from legislation signed earlier this year by President Barack Obama canceling a pilot program that had allowed Mexican trucks to carry cargo on U.S. roads. In March, the Mexican government retaliated by slapping tariffs on $2.4 billion of U.S. goods.

Affected U.S. industries, many facing import duties of 10% to 20% of a product's value, have been urging the administration to resolve the spat. "During this time of historical job loss, we should be doing everything we can as a country to ensure commerce and trade flow as freely as possible," said Scott Openshaw, a Grocery Manufacturers Association spokesman.

Canacar said its members have lost money and missed business opportunities because Mexican truckers have been restricted to operating within 25 miles of the border on the U.S. side. Mexico City's position is that this restriction violates Nafta.

Nafta called for creating a trans-border trucking program by 2000. But it never materialized mainly because of opposition from the International Brotherhood of Teamsters and its allies in Congress, who have argued that Mexican trucks are unsafe, that some drivers don't know English, and that Mexican authorities don't keep adequate safety records on drivers.

U.S. Transportation Secretary Ray LaHood has been working with members of Congress, industry officials and union representatives to craft a new program that would satisfy safety concerns and reopen the roads to Mexican-based truckers.

Mr. LaHood said on May 21 that his proposal contains "good metrics" for testing the safety of Mexican trucks and assuring that drivers are properly licensed.

Sen. Byron Dorgan (D., N.D.) inserted the language that killed the cross-border trucking program into a spending bill this year. A spokesman declined to comment on the issue Monday.

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