Radical students threw firebombs and rocks at police and barricaded streets Tuesday and their leaders vowed to defy the government and march to communist North Korea to press for reunification.

Fierce fighting erupted around Soongshil University when radical students screaming anti-government slogans poured out of the school to attack riot police. Several officers hit by firebombs were covered in orange flames before other police extinguished the fires.Radical students from across the capital had gathered at the school to mourn a Shoonshil student who died Monday of wounds suffered when he set fire to himself two days earlier in an anti-government protest.

Police rifle squads and armored vans fired hundreds of rounds of tear gas, but were forced back from the road in front of the school several times by students armed with wooden poles and iron bars.

Several police officers and students were injured by rocks and other missiles, but police had no figures. Police did not report any arrests.

Up to 60,000 riot police will be deployed to prevent students marching from Seoul to the border and to step up security around key government buildings and college campuses, police officials said.

Radical students planned to march to the border truce site of Panmunjom, which is off limits to civilians, to meet with North Korean students.