South Korea's prime minister and the entire Cabinet offered their resignations to President Lee Myung-bak following widespread protests over the planned resumption of U.S. beef imports.
Spokesman Lee Dong-kwan did not say whether the president would accept the resignations.
The government agreed in April to lift almost all restrictions imposed on imports of U.S. beef over fears of mad cow disease. The decision sparked weeks of protests demanding the government scrap or renegotiate the beef deal amid the perception that it was not doing enough to protect citizens.
Large rallies were expected later Tuesday, with civic groups saying hundreds of thousands of people would hold candlelight vigils throughout the country.
"President Lee hasn't listened to the voices of his people. We still don't have a genuine democracy in our country," said Jang Dae-hyun, a spokesman for a civic group that has organized protests.
Police said they will mobilize about 21,000 riot officers in Seoul and barricade roads leading to the presidential Blue House. Police also placed shipping containers in a major city intersection near the Blue House, blocking traffic.
Rallies against the deal turned violent Sunday and the government said it will take tougher steps against protesters if the violence continues.
Meanwhile, thousands of conservative activists supporting the deal staged protests Tuesday in a Seoul plaza where anti-U.S. beef rallies were to take place later.
"It's time to put out the candles," said Suh Jung-kap, a conservative activist at the site. The protesters "are only interested in overthrowing the Lee Myung-bak government, not the safety of public health."
He said his group members will try to prevent opposing protesters from entering the site, raising the potential of clashes between the two sides.
Prime Minister Han Seung-soo tendered his resignation along with other government ministers to President Lee Myung-bak, according to the presidential Blue House and the prime minister's office.
Government ministers conveyed their intention to step down to Han during a weekly Cabinet meeting earlier Tuesday, the president's spokesman said.
Eight senior presidential secretaries had already offered to quit last week to take responsibility for the beef dispute, but Lee has not decided whether to accept those resignations.
Lee's government said it has asked the U.S. not to export beef from older cattle — considered at greater risk of mad cow disease — but rejected calls for a complete renegotiation of the accord, citing possible diplomatic and trade disputes with the U.S.
Both Seoul and Washington insist U.S. beef is safe, citing the Paris-based World Organization for Animal Health. But protesters say they can't trust what Lee says.
Scientists say mad cow disease spreads when farmers feed cattle recycled meat and bones from infected animals. The U.S. banned recycled feeds in 1997. In humans, eating meat products contaminated with the illness is linked to variant Creutzfeldt-Jakob disease, a rare and fatal malady.