South Korea's opposition has agreed to end its boycott of the legislature over the government's policies regarding U.S. beef imports.

Lawmakers from the ruling Grand National Party reached a compromise agreement with the opposition Democratic Party Tuesday to restart meetings this Thursday.

The two sides agreed to revise a livestock epidemic law to reflect public concerns over U.S. beef safety. They also agreed to investigate the government's decision to reopen markets to U.S. beef.

The move came a day after South Korean President Lee Myung-bak fired three top ministers. Thousands of South Koreans have been protesting since Mr. Lee's government agreed to lift a ban on U.S. beef imports in April.

The protests forced Seoul to renegotiate the deal, which now limits imports of beef from cattle older than 30 months.

Older cattle are considered to be more susceptible to mad cow disease.

On Monday in Washington, the U.S. administration criticized the Democratic-party controlled Congress for refusing to ratify a free-trade agreement with South Korea.

Undersecretary of Commerce Christopher Padilla warned that the United States' hesitancy to sign the deal with a major Asian ally would give China a chance to win more influence in the region.   

Some information for this report was provided by AFP, AP and Reuters.