Tens of thousands of South Korean workers on Wednesday held nationwide rallies and partial strikes to oppose a free trade agreement with the United States and demand better working conditions.

Chanting "Down, down FTA," some 9,000 protesters held a peaceful rally near the city hall in central Seoul, while some 400 farmers out of 3,000 clashed with police in the southwestern city of Gwangju but no injuries were reported.

The protest comes less than two weeks before South Korean and American negotiators meet for their fifth round of free-trade talks in the U.S. to hammer out an accord that would slash tariffs and other trade barriers.

Seoul and Washington kicked off the negotiations in June and have since made some headway in their previous talks but they are unlikely to wrap up an agreement by the end of this year as originally hoped.

A free-trade agreement would slash tariffs and other barriers on a wide range of goods and services from the two nations, which already do $72 billion worth of business a year. If successful, a pact would be the biggest for Washington since the North American Free-Trade Agreement of 1993.

The plan has drawn strong resistance from South Korean labor, agriculture and social groups, as well as the film industry. Farmers have been among the most vocal in protesting against any reduction in protections for agriculture, particularly rice.

Some 80,000 workers participated in Wednesday's rallies in major cities across the country, including some 20,000 near the city hall in central Seoul, claimed Woo Moon-sook, a spokeswoman for the Korean Confederation of Trade Unions, one of South Korea's two umbrella labor groups.

Police said that the protests drew about 65,000 people across the country, including 9,000 in Seoul. About 7,700 police were deployed near the city hall in Seoul.

The South Korean government has vowed stern measures, calling the strike a "political strike."

Thousands of unionized South Korean teachers held a separate rally near the city hall in Seoul in protest of a government plan to introduce a new evaluation system for teachers. They joined a main rally later Wednesday.

Some 45,000 unionized members of Hyundai Motor and its affiliate Kia Motors also staged a four-hour walkout to voice their opposition to a free trade agreement with the U.S., according to labor unions for Hyundai Motor and Kia Motors.

Labor Ministry said most of 58,000 striking workers went on partial walkout.