The United States and South Korea are each gearing up for a crucial vote to ratify a major trade liberalization deal. In South Korea, opponents of the pact are trying to block a separate compromise to open up the country to American beef imports - a crucial step in getting the free trade deal passed in Washington. VOA Seoul correspondent Kurt Achin has more.

South Korean cattle farmers and their supporters came out in force, Thursday, one day before a scheduled parliament session expected to be dominated by debate about trade with the United States.

"Stop imports of U.S. beef!" shouts the crowd of nearly 10,000 people, in a street rally near Seoul.

U.S. beef imports were banned here after a single American animal was diagnosed with the fatal nervous disorder known as "mad cow disease" in 2003. The fatal disease can be transmitted to humans eating meat from an infected animal.

South Korea began resuming imports of boneless U.S. beef last April, then re-imposed the complete ban after bones were found in several shipments.

Last May, the United Nations effectively backed Washington's assertions that American beef is safe. Last week, South Korea announced it would fully re-open its beef market, removing the final political obstacle to a much broader trade liberalization deal between the two countries.

The purported health threat of U.S. beef imports is a rallying cry South Korean producers invoke interchangeably with the far more imminent economic threat.

Fifty-six-year-old farmer Lee Chang-bae says the market price of cattle feed has doubled recently, and that it is getting impossible for farmers to live. He asks who will protect consumers' health, now that the import ban has been lifted.

American agriculture officials point out there have only been two documented cases of mad cow disease in U.S. cattle - neither of which made it into the food supply. American beef producers are cynical about their South Korean counterparts' emphasis on health concerns - saying it is a mask for trade protectionism.

"It's interesting to me that, when Koreans travel to America, no one thinks twice about having 'LA kalbi' or T-bone steaks. They don't think about their safety," said Tami Overby, the president and chief executive officer of the American Chamber of Commerce in Korea.

Three of South Korea's liberal parties say they will open hearings Friday aimed at delaying or even blocking U.S. beef imports. President Lee Myung-bak's conservative Grand National Party, which won a majority in recent elections, is calling for a nationally televised debate on the issue, rather than parliament hearings.

American lawmakers say failure to resume U.S. beef imports here in South Korea could seriously threaten the passage of the two-way free trade agreement signed last year. That deal, which covers everything from automobiles to insurance, would boost the already robust American-South Korea trade relationship by an estimated $20 billion a year.