Protesters, Police Clash in Boston

After four days of relative calm, protests became tense outside the site of the Democratic National Convention (search) as demonstrators burned a U.S. flag and a two-faced effigy depicting President Bush on one side and Sen. John Kerry (search) on the other.

About 400 protesters marched Thursday through the city before arriving outside the fenced-in demonstration area near the FleetCenter, where a shoving match erupted as the throng pressed up against police officers who used clubs to keep the crowd at bay.

Several protesters were dragged from the crowd and handcuffed by police. Others screamed at the officers to let them go.

Demonstrations had started on Sunday, the day before the convention. Two people were arrested Thursday, the event's final day, for disorderly conduct and a third for assault and battery on a police officer. Officers confiscated bolt cutters from one of the people who was arrested and a fake incendiary device -- a papier-mÆachÄe Molotov cocktail (search) -- from another, said Boston police spokeswoman Beverly Ford.

Still, protesters insisted they were being misrepresented as violent instigators.

"These anarchist kids are not who you think they are," said Charles Shaw, 34, a Green Party activist from Chicago (search).

Police quickly barricaded the streets near the FleetCenter as the enormous contingent of state and local officers calmed the situation. Fifty to 60 officers with helmets and riot shields marched toward where the confrontation was taking place.

Police Superintendent Robert Dunford said he got punched as he ran to the aid of his officers. "I tried to pull my officers from the crowd and I got sucker punched from behind," he said.

The main entrance to the FleetCenter, which faces the protest area, was briefly closed just as Democratic delegates were beginning to arrive.

Six protesters were injured by police, but none seriously, said Elly Guillette, of the Bl(a)ck Tea Society, an ad hoc group of self-described anarchists and anti-authority activists formed a year ago to stage protests for the convention.

Bl(A)ck Tea members joined with anti-war groups in a march that began in Copley Square shortly after noon and quickly grew into the largest demonstration since thousands of anti-war and anti-abortion protesters greeted delegates on Sunday as they arrived in the city.

The crowd, estimated at around 400 people, looped through the city's Financial District before heading toward the FleetCenter. They were accompanied by about 100 police officers wearing helmets and carrying shields. Seven protesters with hoods tied themselves to a police barricade.

When they arrived outside the fenced-in demonstration zone near the FleetCenter, the protesters set fire to a two-faced effigy -- one side showing Bush, the other Kerry. As it burned, the protesters stomped on the puppet, while others burned copies of Bush's biography.

Police tactical teams were out in force Thursday.

"I think the cost of not being prepared is watching the city burn down," Superintendent James Claiborne said. "We wouldn't want to see Newbury Street with half the windows knocked out. You know you wouldn't want to see riots in the street and people being hurt."

The biggest protests were on Sunday. About 2,000 anti-war activists and a separate group of 1,000 abortion opponents crossed paths briefly as they marched to the FleetCenter.