Police arrested more than 30 people who crossed a barricade and blocked entrances at the Internal Revenue Service building Wednesday morning, the start of a day of protests nationwide that mark five years since the U.S. invasion of Iraq.

A marching band led protesters down the street near the National Mall and around the IRS building before about 100 gathered at the main entrance. As police began the arrests, some protesters shouted "This is a Crime Scene" and "You're Arresting the Wrong People."

Click here for local coverage on MyFoxDC.com.

Brian Bickett, 29, was among the first arrested. The high school theater teacher from Brooklyn, N.Y., said he had never engaged in civil disobedience before.

"We need to find lots of different ways to resist the war, and I decided to try this," he said.

The demonstrators said they were focusing on the IRS because it gathers taxes used to fund the war. A spokeswoman for the Federal Protective Service said 32 people were arrested.

About 150 people, mostly with the group Veterans for Peace, marched down Independence Avenue. Many of them carried upside-down American flags.

"That is the signal for distress at high sea and we feel the nation is in distress," said 68-year-old George Taylor, a Navy veteran from Takoma Park, Md. Taylor said he had been against the war in Iraq from the beginning. "I'm proud of my country. I'm proud of my service to my country. But I'm not proud of what my government is doing now."

The marchers' first stop was the National Museum of the American Indian, where they were met by American Indian folk singer Buffy Sainte-Marie, who sang her Vietnam-era peace anthem "Universal Soldier."

Anti-war protests and vigils were planned throughout the day around the nation. In Ohio alone, more than 20 different vigils, rallies, marches and other events were planned across the state.

At the American Petroleum Institute in downtown Washington, dozens of protesters held signs reading "Out of Iraq" and "No war, no warming," and chanted "No blood for Oil!"

Craig Etchison, 62, a retired college professor from Cumberland, Md., and a Vietnam veteran, said he has been protesting the war for years.

"I've watched with horror as Bush has lied about this war," he said in front of the building. "I'm appalled at the number of civilians we've killed just as we did in Vietnam."

Protesters tried to block traffic, sitting in the street and linking arms. At least once, they were dragged away by police.

Meanwhile, a handful of people gathered at a nearby armed forces recruiting center, holding signs such as "We support our brave military and their just mission."

"We're out here to show support for our troops on the anniversary of the liberation of Iraq," said Kristinn Taylor, 45, of Washington.

College students from New Jersey to North Dakota have planned walkouts, while students at the University of Minnesota vowed to shut down military recruiting offices on campus.

"This is the first time coordinated direct actions of civil disobedience are happening," said Barbra Bearden, communications manager for the group Peace Action. "People who have never done this kind of action are stepping up and deciding now is the time to do it."

In Miami, half a dozen anti-war protesters dressed in black placed flowers outside the U.S. Southern Command during rush-hour Wednesday morning.

"What happens in South Florida is part of what happens in Iraq," said Warren Hoskins, president of Miami for Peace, as he gestured toward the Southern Command. "People who come through here may go to Guantanamo Bay but next they may go to Abu Ghraib."

In Vermont, about 30 people protested in rain and sleet in front of defense contractor General Dynamics Corp. in Burlington on Wednesday morning, some locking arms to block workers from entering the parking lot.

Protester Jonathan Leavitt, 29, said he showed up "to say no to war profiteering and yes to building a peace economy."

On Tuesday, 10 people were arrested at an anti-war rally in upstate New York. About 60 people participated in the demonstration, which started at Binghamton University campus and moved into the street as demonstrators made their way to a military recruiting station. Police said the demonstrators tied up traffic in the town of Vestal, N.Y., causing two traffic accidents.

The Iraq war has been unpopular both abroad and in the United States, although an Associated Press-Ipsos poll in December showed that growing numbers think the U.S. is making progress and will eventually be able to claim some success in Iraq.

The findings, a rarity in the relentlessly unpopular war, came amid diminishing U.S. and Iraqi casualties and the start of modest troop withdrawals. Still, majorities remain upset about the conflict and convinced the invasion was a mistake, and the issue still splits the country deeply along party lines.

Activists cite frustration that the war has dragged on for so long and hope the more dramatic actions will galvanize others to protest.