He said it was the first time that any country had agreed with any other country to limit domestic subsidies.

There also would be a ceiling on the level of domestic subsidies based on a percentage of the country's total agricultural production.

Washington defended the additional financing as domestic subsidies that do no harm to global markets.

"Export subsidies are now gone, and trade-distorting domestic subsidies are on their way out."

Indeed, he said the United States would cut some domestic subsidies by "up to 50 percent if I get market access."

But the two countries' economies are so intertwined that domestic subsidies inevitably affect trade between them.

These policies enforced high tariffs and large domestic subsidies to encourage domestic production as a substitute for imports.

The agriculture negotiations have stalled, largely because of a reluctance by the European Union to accept steep cuts in domestic subsidies.

The United States also needs to improve its agricultural proposal by reducing domestic subsidies and food aid programs that distort trade.

The preliminary ruling, which is expected to be upheld in June, was the first successful challenge of a wealthy nation's domestic agricultural subsidies.