Reuters says efforts to ratify the South Korea-U.S. free trade agreement (FTA) could spark a major fight within the U.S. Democratic Party unless Seoul agrees to major changes in the deal.

The report quoted Representative Louise Slaughter, a leader of trade-wary Democrats, as saying Monday that there are significant changes that must be made in order for the Korea-U.S. free trade agreement to gain broad congressional support.

Many Democrats have called for revisions to the trade pact, saying the deal contains content that threatens the U.S. market, including a clause that requires the United States to immediately eliminate a two-and-a-half percent tariff on most South Korean cars.

As a result, U.S. President Barack Obama's plan to send the free trade pact with South Korea to Congress by early 2011 is likely to run into difficulties.