South Korean and U.S. negotiators have concluded their final round of formal talks aimed at a free trade deal. Although they say a deal is close, some of the most sensitive issues remain to be worked out in informal meetings, which may require the intervention of higher-level officials on both sides. VOA's Kurt Achin reports from Seoul.

U.S. senior trade negotiator Wendy Cutler told reporters in Seoul Monday that four days of intensive talks aimed at a free trade deal with South Korea have made "significant headway.

"The United States remains committed to completing this agreement by the end of March," she said, "and the unprecedented progress we've made here this week in our eighth and final round gives me increasing confidence that we can do this."

The Free Trade Agreement, or FTA, could add tens-of-billions of dollars to the already robust U.S.- South Korea trade relationship by making it easier for the two countries to buy and sell each other's goods.

However, chief South Korean negotiator Kim Jong-hoon agreed with Cutler Monday that sensitive issues still require hard work and attention.

Kim says automobiles and marine products are among the items, which still require negotiation.

The United States exported about five-thousand automobiles to South Korea in 2005, while U.S. consumers bought more than 700-thousand South Korean cars.

Agriculture, especially rice, is also a highly sensitive issue in the talks, symbolizing what many South Koreans perceive as the danger of far larger U.S. industries overwhelming smaller Korean ones.

Wendy Cutler says she and Ambassador Kim will meet again in Washington next week to discuss the most sensitive issues.

"I think it's safe to say that, no matter how hard we work, that there will be, even after our work in Washington next week, a handful of issues that need to be elevated above the chief negotiator's level," she said.

Cutler says senior U.S. envoy Richard Crowder will visit Seoul next week to seek more progress on the agriculture issue, as well as on South Korean imports of U.S. beef.

South Korea agreed last year to resume U.S. beef imports, which were suspended after a U.S. cow was found to have mad cow disease in 2003. However, all shipments this year have so far been rejected, after South Korean inspectors found small bone chips they say pose a danger. U.S. officials say American beef is safe, and the World Organization for Animal Health said this week U.S. producers have controlled the threat of mad cow disease.

U.S. and South Korean negotiators are working on a tight timeline. The Bush administration must submit any proposed deal to Congress by April 2, in order for it to come to a simple yes-or-no vote. After that deadline, Congress may seek to amend a deal, greatly reducing chances of passage.