The government's announcement came despite widespread public opposition to the beef deal, which critics say fails to adequately protect against mad cow disease. About 9,000 people took to the streets in Seoul on Thursday night to denounce the move.

Three main opposition parties filed lawsuits Friday asking the Constitutional Court to rule that the government's move violates the people's right to health, and to issue an injunction against a resumption of imports until it issues a verdict.

They also demanded that all Cabinet members resign.

Constitutional Court spokesman Judge Kim Bok-ki said the court will deliberate the case expeditiously, but he did not give a timeframe.

Quarantine inspections of American beef shipments are expected to begin next week.

Still, U.S. beef is not expected to become widely available immediately because four major discount chains say they have no plans to put it on their shelves because of negative public perceptions of American beef.