MEXICO CITY, June 5 (Reuters) - U.S. sugar refiners came back to the negotiating table with additional demands after the U.S. and Mexican governments had reached a deal in a dispute over trade in sugar on Monday, a source close to the talks said.
Those demands are "impossible" to meet and the strategy seems to be a "moving target from petitioners to blow the deal," the source said, adding that the demands included conditions on the right of first refusal that would be difficult to meet.
The talks on sugar trade are seen as a precursor as well as significant hurdle to the more complex discussions on the North American Free Trade Agreement (NAFTA) between the United States, Mexico and Canada, which are expected to start in August.
The source said the cane refiner ASR Group, the maker of Domino Sugar, was "the real headache" in the talks. (Reporting by Anthony Esposito)