SEOUL, JUNE 26 -- Around 8 p.m., as antigovernment protests swept the city, about 200 retreating students came crashing through the glass doors of the Hilton Hotel lobby. They were seeking refuge from a fierce rock and tear gas battle with police that had erupted in the hotel's front parking lot.

Foreign business executives, tourists and hotel employes gaped in astonishment as the students sat down on the lobby's marble floor and waited, sometimes singing political songs and chanting antigovernment slogans. They left within about 90 minutes, having caused no damage. The police had departed as well.

But the startling enactment of student-police conflict in a foreigners' oasis in Seoul was not quickly forgotten. For hours afterward, anyone passing through the lobby choked on the tear gas fumes that wafted into the hotel along with the students.

In many sections of Seoul today, life turned into a jumble of chaos and confusion as mass demonstrations against the government resumed.

The protest rally, which organizers called the Grand Peace March for Democracy, was supposed to end up at Pagoda Park, a symbol of Korean resistance to Japan's occupation of the country from 1910 to 1945. Most of the demonstrators never got there.

Riot police commanders, using a common strategy, sealed off the park and stationed hundreds of men in military fatigues and Darth Vader-style helmets at key gathering points.

Three hours before the demonstrations were supposed to begin, authorities blocked off subway stations near the gathering points.

Many major hotels in the area advised guests not to venture downtown this evening. Officials at the U.S. Embassy, concerned over anti-American sentiments sometimes expressed by demonstrators, closed the embassy early today. U.S. military television also advised U.S. citizens to stay away.

By 6 p.m., the mood was electric. Clusters of bystanders waited at bus stops in near 90-degree heat, prepared with handkerchiefs and cellophane wrap to protect their eyes and noses from the stinging tear gas.

In front of the Seoul Plaza Hotel, several hundred demonstrators gathered but were quickly dispersed by riot police tossing tear gas grenades. Guests at the hotel became unwilling participants in the political turmoil.

"Those sons of bitches, why are they doing what people dislike?" shouted one man, angrily waving his newspaper at the riot police. "People do not like it, and I don't understand why they are doing it."

Around the corner, a team of medical students wearing white coats used a saline solution to treat a student overcome by tear gas. "Even though this is risky, this is our most important task -- to treat wounded people," said one medical student from Seoul National University.

Along Seoul's Chongan Avenue, people made it clear by word and action that their sympathies were with the students. Some car and municipal bus drivers honked their horns as they passed demonstrating students. Businessmen in dark suits and ties applauded to signal their support.

One shopkeeper who closed her clothing store early tonight said the protests have hurt her income. But, she said of the protesters, "I have to support them more, because I think what they are doing is right."

About 5,000 people chanting "Down with dictatorship" gathered in front of the massive stone East Gate. A squad of riot police throwing tear gas grenades every few minutes was almost unnoticeable.

At Seoul's main railway station, fighting was fierce between students and police as night fell. Rocks and splotches of white tear gas powder covered the broad avenues.

As close-order formations of police charged against retreating students, hurling gas grenades before them, people came stumbling out of buses trapped in the traffic jams. Police almost never close off streets to traffic during demonstrations in the apparent belief that full streets will deny protestors a place to gather.

Some found new uses for the long rows of public telephone booths outside the station. Whenever police let fly with new volleys, the booths filled with people seeking shelter from the canisters, which skipped across the pavement like flat stones on a pond.