Reaching a U.S.-South Korea trade deal that boosts American exports and creates jobs is more important than rushing to clinch an agreement, U.S. Trade Representative Ron Kirk said.

Kirk, in an interview with Reuters, also said that China's recent limits on exports of rare earth minerals vital to high-tech products, were a "wake up call" about the risk of relying on one country for supplies, but gave no indication that Washington would complain to the World Trade Organisation (WTO)

The United States and South Korea failed to reach agreement on the trade deal in talks in Seoul, jeopardising the pact signed three years ago and embarrassing both.

"I think it's much more critical that we get it right than we rush to just take an agreement for the sake of saying we've got an agreement," Kirk told Reuters in an interview on the sidelines of an Asia-Pacific summit in Yokohama, south of Tokyo.

Analysts have said a final agreement could languish for another year or more.

The deal, if ratified by the two countries' legislatures, would be one of the largest free trade pacts ever and the largest signed by the United States since the North America Free Trade agreement with Canada and Mexico that took effect in 1994.

Studies say the deal would boost the $66.7 billion in annual two-way trade by as much as 25 percent.

"...The one thing all Americans agree on is that a 9.6 percent unemployment rate in their minds is at least 9 points too high," Kirk said.

"We are focused on what we can do in a thoughtful way to help us in an honest way put jobs on the table and so, from the president's perspective, we can't get this deal done soon enough," Kirk said, noting that U.S. President Barack Obama had said the aim was to get an agreement in "weeks, not months."

The two sides were working hard to address U.S. congressional and industry concerns that the deal, signed in 2007, did not do enough to open South Korean markets to U.S. cars and beef. (Reuters)