The United States has offered a "revised proposal" to South Korea in their unofficial meeting on the impasse over Seoul's resumption of U.S. beef exports, a South Korean government official said Tuesday.

"The revised proposal was made by U.S. Trade Representative Susan Schwab in an unofficial meeting in the afternoon of June 16 (Washington time) with Trade Minister Kim Jong-hoon," the South Korean government official told Yonhap News Agency on condition of anonymity.

"Although there are some improvements in the revised proposal, it is still far from our expectations," the official said, declining to elaborate further.

Minister Kim and Schwab have held talks since Friday to strike solutions to South Korea's latest political turmoil triggered by the signing of a beef import deal in mid-April.

The deal envisioned lifting a ban on U.S. beef imports many South Koreans believe are susceptible to mad cow disease.

The pending resumption of U.S. beef imports has triggered huge anti-government demonstrations in South Korea.

South Korean negotiators give top priority to obtaining the U.S. government's assurances in the written form to encourage American exporters to voluntarily refrain from exporting beef from cattle aged 30 months or older. Younger cows are believed to be less at risk from mad cow disease.

However, the U.S. government has been reportedly reluctant to do so, saying the South Korean request would run counter to international trade rules.

Since the beef deal was announced on April 18, street rallies and candlelight vigils have been held in Seoul and other major cities almost everyday. Mounting public anger has rapidly evolved into huge anti-government protests, leading South Korea's Cabinet to offer to resign last week.

The United States once accounted for more than two-thirds of South Korea's beef imports, exporting $850 million to South Korea a year. But South Korea banned beef imports from the U.S. after a case of mad cow disease was found in the U.S. in 2003.