SEOUL, South Korea (CNN) -- South Korean President Lee Myung-bak promised a "fresh start" Wednesday after his entire Cabinet and top civil servants offered to resign following street protests.
Tens of thousands hold up candles during Tuesday's protest against resuming beef imports.
"I'm determined to make a fresh start. Let's pursue aggressive challenges in these difficult times," Lee said in a statement that may indicate sweeping government personnel changes are in the works.
The government has been in crisis over a deal to resume imports of beef from the United States after a ban lasting several years due to fears of mad cow disease.
Tens of thousands of protesters took to the streets of the South Korea capital, Seoul, on Tuesday over the deal with Washington.
Prime Minister Han Seung-soo and the South Korean Cabinet offered to resign Tuesday. The move followed a similar resignation offer last week by eight top Lee aides.
Washington and Seoul reached an agreement in April that would clear the way for South Korea to resume importing beef from the United States, but Seoul now has reservations over the terms of the agreement, and South Korean negotiators held meetings in Washington on Wednesday to try to change the terms of the deal. Watch massive protests in Seoul »
Lee instructed them "to ensure that beef from cattle 30 months old and older will not be imported under any circumstances," his Web site said. "It will not be easy, but I urge you to do your best to realize what the people want in this matter."
The South Korean move stems from concerns that animals more than 30 months old are a greater risk for mad cow disease.
The U.S. Food and Drug Administration bans the use of certain organs of cattle more than 30 months of age because they represent a greater threat for mad cow disease, but the agency considers the meat from those animals to be safe. While the United States already agreed not export the cattle organs considered most likely to carry disease, the deal put no age restrictions on cattle.
Last week, the South Korean government put off the final administrative step needed to resume imports. Without that step taking place, no beef will be imported from the United States.
Eating meat products contaminated with the illness has been linked to variant Creutzfeldt-Jakob disease, a rare and fatal malady in humans.
Scientists believe mad cow disease spreads when farmers feed cattle recycled meat and bones from infected animals.
The U.S. banned recycled feeds in 1997.
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