Seoul: South Korean protesters fought with police on Sunday amid a deepening political crisis over US beef imports, hours after their president appealed to Washington to help ease growing public anger.

A pledge from US President George W. Bush on Saturday to address South Korean fears of mad cow disease from American beef appeared to do little to calm protesters' anger at President Lee Myung-bak.

The clashes erupted early on Sunday after a crowd estimated by police at about 40,000 rallied in central Seoul against an April agreement to resume US beef imports, which they say failed to protect against beef potentially tainted with mad cow disease.

Demonstrators attacked police riot-control buses lined up to barricade downtown streets, using ladders to smash the vehicles' windows and trying to overturn them.


Clashes ensued, with protesters hitting police with sticks and officers striking back with riot shields. Police and protesters fought each other on top of at least one of the buses.

Protest organisers said at least 20 demonstrators were hurt. Seoul National University Hospital said it treated six injured people and all were released. Some police also were hurt, and 11 people were taken in for questioning.