The U.S. and South Korea are nearing an agreement to resume imports of American beef suspended over fears of mad cow disease, a South Korean government official said Monday. While a time frame is unknown, the market is expected to open after the United States addresses South Korean concerns over how beef at U.S. slaughterhouses is processed.

South Korea was the third-largest foreign market for American beef after Japan and Mexico when it shut its doors in December 2003, after the U.S. reported its first case of mad cow disease.

The government agreed in January to allow imports of beef from American cattle younger than 30 months, but the re-opening has stalled over measures to ensure meat safety. South Korea wants U.S. beef processed separately from foreign beef in U.S. facilities. It also wants equipment used on older cows to not be used to process the younger ones. Officials in South Korea believe the younger cattle are safer because they were born after the U.S. took anti-mad cow measures.