Opposition leaders today called on people to pour into the streets on Friday to force President Chun Doo Hwan to give up power, while a U.S. envoy cautioned Chun not to use soldiers against demonstrators.
A new opposition alliance called the National Coalition for a Democratic Constitution called for the nationwide protests Friday in its campaign to oust the government.
Radical students said they will march the same day on the Blue House, the presidential residence in Seoul.
National police chief Kwon Bok Kyung issued a statement saying the protests were illegal and his 120,000 men would take "stern action" against violence.
Security was increased around important public buildings and the U.S. Embassy warned Americans to stay off the streets.
"The reckless and illegal demonstrations planned by the National Coalition for June 26 are aimed at driving society into extreme chaos and anxiety to achieve its subversive political objectives," Kwon said.
After meeting with leaders of the Chun regime and the opposition today, U.S. Assistant Secretary of State Gaston Sigur urged both sides to negotiate a peaceful solution.
"Our position is crystal clear," Sigur said. "We oppose martial law and would hate to see anything like that happen in this situation. Any use of the armed forces in this situation is unwarranted."