U.S. and South Korean trade officials pressed ahead with negotiations that Seoul hopes will result in new limits to a recent deal to reopen South Korea's market to U.S. beef exports.
Ministers held "intense discussions" on technical issues and will meet again on Wednesday, a spokeswoman for U.S. Trade Representative Susan Schwab said.
"This is a complex issue, but both sides remain committed to finding a mutually agreeable path forward," USTR spokesman Gretchen Hamel said.
Officials have been huddled in private discussions on the April beef agreement since South Korean Trade Minister Kim Jong-hoon arrived in Washington on Friday, but so far neither side has heralded a breakthrough.
The Bush administration said it continued to seek a "mutually agreeable path forward" to the conundrum surrounding the beef deal, which has unleashed major problems for the young presidency of South Korean President Lee Myung-bak.
Seoul is now looking for assurances that U.S. exporters will restrict beef shipments, once resumed, to products from cattle less than 30 months old, a step it hopes will quell concerns among South Koreans about mad cow disease.
The United States has long insisted its beef is safe, and is looking to regain access to several key markets in Asia and rebuild exports crippled by the discovery of mad cow disease in the United States in 2003.
Administration officials are eager to resume beef trade as well so they can move ahead in lobbying Congress to approve a major bilateral trade deal with South Korea.
Both sides want to avoid the perception of a renegotiation to the agreement, which might create additional problems in Congress for the trade deal and weaken the U.S. case for fully reopening other markets.
The beef agreement, along with fears about President Lee's economic reform plans, has been a flashpoint in South Korea, fueling protests and a truckers' strike that is costing exporters billions of dollars.
On Tuesday, a labor group with more than 600,000 members announced it would hold a major one-day strike in early July.