South Korean President Lee Myung-bak said Wednesday his government intends to make a fresh start after his entire Cabinet offered to resign following weeks of anti-government rallies over plans to resume imports of U.S. beef.

His remarks came hours after about 80,000 people demonstrated into early Wednesday morning in Seoul in the largest protest yet against the U.S. beef deal, part of nationwide rallies tied to the anniversary of pro-democracy protests in 1987.

Lee himself was arrested in 1964 as an anti-government protester and given a suspended sentence for Animal Health.

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"I had a lot of mixed feelings watching last night's street rallies. I myself participated in pro-democracy activities as a student in the past," Lee told businesspeople during a meeting at the presidential office.

"The government intends to make a start with a new determination," he said.

Lee also said he was concerned the Cabinet resignations might cause "a vacuum in state affairs" as the country faces rising oil prices and other economic difficulties.

Lee has not yet said whether he will accept the resignations, but was expected to reshuffle a few ministers, which would not affect his ability to serve out his single five-year term. He was not expected to make a decision on the Cabinet for several more days.

The Cabinet's offer to resign was an attempt to defuse the beef crisis, which has sparked weeks of protests and paralyzed Lee's government less than four months after the former Hyundai CEO took office following a landslide election victory.

What started as a trickle of small protests against the beef deal with the U.S. has swelled into a torrent of anti-government street rallies, invoking the memory of pro-democracy movements in the 1980s that brought down the then-military dictatorship.

Lee, a pro-American conservative, agreed in April just before a summit with President Bush to reopen the country's beef market — resolving an issue that had long been an irritant in bilateral ties.

South Korea was the third-largest overseas customer for U.S. beef until it banned imports after a case of mad cow disease — the first of three confirmed in the United States — was detected in 2003.

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 he has rejected calls for a complete renegotiation of the accord, citing possible diplomatic and trade disputes with the U.S.

"We're not considering a renegotiation," South Korean Deputy Trade Minister Ahn Ho-young told reporters Wednesday. "If we break our promise, the consequences are enormous. South Korea will become an unreliable country."

Both Seoul and Washington insist U.S. beef is safe, citing the Paris-based World Organization.