Clinton arrived for talks with the RoK’s Foreign Minister Kim Sung-hwan Saturday and President Lee Myung-bak Sunday, before a trip to Japan in a gesture of support following last month's earthquake and tsunami disasters that killed thousands and crippled a nuclear plant.

The shift in focus to Asia follows Clinton's attendance at a NATO conference in Berlin where the alliance's foreign ministers faced strains over a Western air campaign in Libya against forces loyal to Muammar Gaddafi.

U.S. and the RoK’s trade negotiators struck a deal in December on a free trade pact, which was signed in 2007 but had not been ratified for three years because of U.S. auto and beef industry concerns.

However, both the Congress and the RoK’s parliament have yet to pass bills to approve the pact, despite U.S. President Barack Obama's renewed push for ratification.

"I'm very encouraged and determined about the passage of the free trade agreement," said Clinton, sitting across a conference table from Kim in Seoul. "We will be consulting and making the case together to our respective legislatures and I'm very confident there will be a positive outcome."

"It is important that we're meeting in the home stretch of the Korean free trade agreement," she added.

Sander Levin, the top Democrat on the U.S. House of Representatives Ways and Means Committee, last month criticized Republicans for refusing to move ahead on the RoK’s deal until the White House sends Congress implementing bills for long-delayed trade agreements with Colombia and Panama.

Republicans broadly support the RoK’s deal, but have threatened to block a vote on the pact unless the White House also submits the other two pending trade deals for approval.

U.S. Trade Representative Ron Kirk has said the Obama administration wants to win congressional approval of a free trade agreement before July. The agreement is currently pending in the RoK's parliament and is expected to be passed.

The U.S. International Trade Commission estimated in 2007 the RoK’s agreement would boost U.S. exports by about US$10-11 billion annually, while increasing imports from that country by about US$6.5-7.0 billion.