(Updates with details, market comment; adds byline, WASHINGTON dateline)
By Chris Prentice and Krista Hughes
NEW YORK/WASHINGTON Jan 16 (Reuters) - Louis Dreyfus Commodities' Imperial Sugar Co and AmCane Sugar LLC have asked the U.S. government to continue its anti-dumping and countervailing investigations on sugar from Mexico, according to U.S. Department of Commerce filings.
The requests represent the shoring up of challenges launched last week by the two companies to a pact finalized by the United States and Mexico to end a dispute over sugar that has plagued the North American marketplace for nearly a year.
Imperial Sugar and AmCane, both U.S. refiners of raw cane sugar, have requested that the Commerce Department continue its probe, and have simultaneously notified the U.S. International Trade Commission (ITC) of the requests, according to documents dated Jan. 16.
These challenges follow requests from both companies that the ITC review the pact hammered out by the Commerce Department and Mexican officials, saying that it did not eliminate harm to their businesses.
Should the ITC decide the deal stands, these requests would require the Commerce Department and ITC to resume their probes, and make a final decision.
The two rounds of challenges could hamper the finalization of the deal announced by the Commerce Department on Dec. 19.
A spokeswoman for Louis Dreyfus and representatives from AmCane could not immediately be reached for comment, given the late hour.
The challenges will likely stoke worries over supplies in the United States, as flows of sugar from its top foreign supplier have dried up after the Commerce Department decided in August and October to levy large duties on Mexican imports.
"It's going to get dicey if this goes into April or later," said Frank Jenkins, president of the largest raw sugar physical and futures broker in the United States. "People will be hesitant to bring sugar from Mexico under these conditions."
Mexico and the United States have been embroiled in a dispute over the sweetener since a coalition of U.S. producer groups asked the U.S. government in March 2014 to investigate dumping of subsidized sugar from Mexico. (Reporting by Chris Prentice in New York and Krista Hughes in Washington; Editing by Lisa Shumaker and Gunna Dickson)