SEOUL - SOUTH KOREAN police clashed violently with protesters opposing US beef imports here yesterday, leaving more than 200 people injured, officials and witnesses said.

Police fired water cannon and wielded batons to try to control protesters, who hit back with poles and steel pipes, smashing police bus windows and spraying street fire hoses.

With rocks also hurled through the air, many of the injured suffered head wounds and were taken to hospitals in ambulances, according to witnesses.

Protesters attempted to topple a police bus, and police discharged hand-held fire extinguishers to quell the violence.

Seoul police reported that they had arrested 55 protesters during the prolonged overnight clashes in which 114 officers were injured, 15 of them seriously.

'Some of our troops suffered serious bone fractures, with one of them sustaining a fractured skull,' a police spokesman said.

Protest organisers claimed that more than 100 citizens had been hurt.

'About 100 citizens were sent to hospitals,' an unnamed protest leader told the Yonhap news agency. But the organisers had no specific data on the injuries.

The violence began late on Saturday when police stopped thousands of protesters from marching to the presidential office after holding a rally which had been attended by about 15,000 people.

US Secretary of State Condoleezza Rice, on a visit to Seoul on Saturday, had urged South Koreans to trust official assurances that beef from the United States is safe, amid fears of mad cow disease.

Seoul had gone back to Washington this month to secure extra safeguards in its US beef import deal after an agreement in April - which allowed the unconditional return of American beef - sparked massive protests.

Despite the extra safeguard of allowing beef only from cattle under 30 months old - which are deemed to be at less risk of mad cow disease - protests have intensified since Seoul's formal resumption of the imports on Thursday. Unionists have threatened to block the release of US beef to the market.

The South Korean government yesterday issued a statement warning against further street protests.

Justice Minister Kim Kyung Han told a televised news conference, accompanied by labour and other security-related ministers: 'The government has no other choice but to take strong counter-measures, including the spraying of tear-gas solution.'

He warned that the authorities would arrest violent protesters and file a lawsuit against vandals who damage police vehicles or equipment.

AGENCE FRANCE-PRESSE