As the threat of war loomed large yesterday, hundreds of students and activists marched from Cambridge to Boston expressing raucous opposition to U.S. policy in the Persian Gulf.

Chanting "One, two, three, four, we don't want your bloody war," about 300 protesters, some wearing gas masks and others smeared with fake blood, blocked traffic as they wound their way through city streets.

The demonstration was generally peaceful, but windows were broken at a federal office building in Boston. In the scuffle which followed, one antiwar activist was arrested.

About 80 Cambridge Ringe and Latin School (CRLS) students left school to join the protest. High school and college students made up the majority of the crowd and prompted chants such as "Money for tuition, not for ammunition."

On their way to Boston, the marchers stopped at CRLS, urging the students inside to join them. As the crowd yelled, " Out of school, into the streets," students pressed their faces to the classroom windows. Some protesters confronted CRLS security guards and handed bumper-stickers to youths through an open door.

Rachel B. Weinstein, a junior at Cambridge Rindge and Latin School, said that many students there had stood up and walked out of classes. Most had parental permission, but others faced disciplinary action, she said. "It's important to be here," Weinstein said, "but it's completely different from school."

"I don't think I'll be able to do any more studying, because I'm going to be working for peace. I've got a paper that I'm just going to take an incomplete on," said M. Emmett Rosenthal '91-'92, one of a handful of Harvard students who participated in yesterday's protest.

At the U.S. Armed Forces Recruiting Center at 955 Mass. Ave., the group stopped to throw snowballs, put stickers on the window, and shout, "I want to kill, let me in." The blinds to the recruiting station were closed and the doors were locked. As snowballs whizzed by his head, a frowning Cambridge police officer complained, "This is supposed to be a peaceful demonstration."

When the crowd reached Central Square, it staged a "die-in." In a busy intersection, about 40 marchers dropped to the ground and cried in feigned agony.

As the group continued towards Kendall Square, stunned bystanders lined the streets, and many motorists added their honking horns to the din of the rally. But some drivers challenged the protesters.

"Freedom to Kuwait. I am for war. Peace for Kuwait. Peace for Israel. Kill Saddam Hussein," said immanuel Glazer, 46, a Soviet Jewish emigre driving a truck which was caught in a traffic jam caused by the protest. "I am strictly for Bush's policy," he said.

Bill and Beth Kostopoulos, proprietors of the Kendall Flower Shop, sold "peace ribbons" to the protesters at prices ranging from 50 cents for a small bow to $1.00 for a large one. Bill remarked that the protesters seemed, "nice and peaceful" and said that he didn't think there would be a war.

Leaving Kendall Square, the group crossed the Longfellow Bridge into Boston. After another brief die-in in Leverett Circle, the protesters continued towards Government Center.

At an Exxon service station along the march route, some protesters applied stickers to a sign and embraced a gas pump. An employee swung at the activist with a squeegee, but failed to make contact.

"He's a businessman. He's not for war," a customer yelled at the marchers.

Another onlooker criticized the marchers for clogging the streets around Mass. General Hospital. "I'm not going to waste my time blocking traffic, especially with ambulances in it," said Whitman, Mass. resident Kerry Williams.

One woman lay down in a Boston intersection and faked death as her cohort zipped her up inside a plastic body bag. One protester called out, "How many bags left? 49,999."

At Boston City Hall, the protesters joined a group of high school students and chanted as television stations did live reports for their noon broadcasts.

At about 12:15 p.m., some of the demonstrators marched to the federal government's Boston headquarters.

Yelling, "This is our federal building!" a protester tried to enter the John F. Kennedy Building and was repelled by security guards. Officers of the Federal Protective Service attempted to close a door to the office building, but protesters held onto it. A tussle ensued and the glass door was shattered.

As police pushed the crowd back with nightsticks, some demonstrators fought with the officers. Snowballs thrown by people in the crowd broke two windows, sending pieces of glass into the building's lobby. During one scuffle, an officer pulled a tuff of hair out of a man's scalp and dropped it on the ground. Another man pushed the officer and was promptly arrested.

Troubled Lunch Hour

The eight security officers, now reinforced by Boston Police and FBI agents who had filtered down from their offices in the building, stood in the lobby waiting for the chanting crowd to move away. Other federal employees going in and out during the lunch hour had difficulty finding an unlocked door that was not blocked by either protesters or police.

Police identified the arrested man as Jonathan Fischer, 28, of Westville, Conn. He was taken to the Area A station and charged with assault and battery on a police officer, a Boston police spokesperson said.

From Government Center, the group, now numbering about 250, moved on to the State House where speakers discussed the evils of war.

Though they were united in their oppostion to war, the protesters clearly held varying views of the best solution to the Gulf crisis, Leaders of the march called for total withdrawal of U.S. troops from the Middle East and a revolution in the United States.

That sentiment troubled one high school student carrying a banner at the front of the march. "We don't want revolution, we just want to make this war not happen," she said.