Radical students seeking revolutionary change are waging a violent struggle in the streets that poses a threat to South Korea's fragile political stability.

The nation has been hit by a new wave of political violence in the past month as the radicals have battled riot police and staged firebomb attacks to press for the fall of the government, expulsion of U.S. troops and unification of the Korean Peninsula."Down with the military dictatorship!" "Yankee go home!" and "Unite our fatherland!" protesters have chanted.

Radical leaders insist that President Roh Tae-woo's government is a front for military rule and domination by the United States, which has 42,000 troops stationed in South Korea.

The radicals reject recent democratic reforms and say they are determined to topple the government and the ruling elite through violence.

Analysts say the students have little chance of achieving their goals.

The radicals account for only about 10 percent of South Korea's 1 million college students.

They have lost support and become isolated as most Koreans have welcomed recent political reforms and rejected the extremism.

But some analysts say the students are nevertheless an explosive and unpredictable factor in a nation with a history of violent and uncompromising political confrontation. They say the radicals are dominating South Korea's politics and derailing the political process.

"This nation is now experiencing a most difficult period. We have the still very serious problem of college campus unrest," said Rhee Chong-ik, a political analyst.

"It is deplorable for the government to have become the prisoner of activist students," said political commentator Chong Un-bung.

The radicals come from all social and economic backgrounds. Children of senior officials and military officers join children of workers and poor farmers in campus groups that embrace a common idealism and anger at government abuses over the years.

The movement is bolstered by anti-government dissidents and intellectuals who for years battled South Korea's authoritarian governments. Some unemployed continue radical activity after college, including many who are blacklisted because of their records and are unable to get good jobs.

Observers worry about the long-term impact of radicalism, since many bright and talented students with potentially important roles in the country's future are attracted to the radical ranks.

The radicals - who are often vague about their goals - say they are fighting for the creation of an idealistic "society of the masses," with students, workers and peasants uniting to end oppression, poverty and exploitation. Radical leaders stress that the solution to the nation's problems is to destroy the power of the military, government bureaucracy and major corporations that dominate the economy.

"We feel in our hearts that something must be done now. People just talk, and the government uses that to continue its rule. We must act to force change," said one leader, who refused to be named.