Seoul, South Korea - Tens of thousands of workers and farmers clashed with a force of 23,000 riot police intent on preventing unauthorized political demonstrations in the run up to the December presidential elections. Protesters had planned to march on the U.S. embassy to show opposition to a neo-liberal free-trade agreement between the two countries that was signed last June but has yet to be signed into law by the U.S. Congress.

Demonstrators were also calling for South Korean troops to withdraw from the U.S.-led conflicts in Iraq and Afghanistan. Workers and environmental advocates have consistently opposed free-trade groups saying that they drive wages down and eliminate hard fought worker and environmental protections as barriers to trade.

Many of the protesters who found their march route blocked by hundreds of riot police and 600 buses used long sticks and stones to take their frustrations out on the police and their buses. Police sources said that some 100 protesters were arrested and that more than 10 riot police and some 50 demonstrators were injured.