Washington's National Air and Space Museum was closed Saturday afternoon after sign-wielding demonstrators tried to storm the building on the National Mall.
At least one person was pepper sprayed when the crowd pinned a guard against a wall and another guard came to his rescue, Smithsonian spokesperson Linda St. Thomas told NBC station WRC.
"You cannot bring that stuff in the museum under any circumstances," St. Thomas told WRC.
Protesters included people from the October 2011 Stop the Machine group and Occupy D.C., an offshoot of the larger Occupy Wall Street movement in New York.
Occupy DC protesters marched on streets in the nation's capital.
About 100 to 200 people arrived about 3 p.m. at the museum, said Smithsonian spokesperson John Gibbons.
Ann Wilcox, a lawyer working with Stop the Machine, said a 19-year-old woman from Madison, Wisc., was arrested by police. She paid a fine and was released later Saturday. Wilcox said the protesters went to the Air and Space museum to demonstrate against a military drone exhibit.
Pete Piringer, a D.C. fire department spokesman, told The Associated Press on Saturday evening that medics treated or evaluated a dozen people at the scene but that no one was seriously hurt by the pepper spray.
The museum is expected to open as usual on Sunday.
New York park gathering
In New York City, an Occupy Wall Street expedition moved from Lower Manhattan to Washington Square Park Saturday.
Organizers planned a "general assembly" to recruit new supporters and share ideas.
"The Washington Square Park thing is a great way to bring us to the next level," said Michael Fix, an organizer of the demonstration.
There were no plans to set up a 24-hour camp in Washington Square Park similar to the one that has operated for three weeks in Lower Manhattan's Zuccotti Park.
The protesters living in Zuccotti Park have built a full-service demonstration staging zone, complete with hot food, health care, a digital counter registering supporters, and a solar energy truck to help supply power to electronics.
First-year medical resident Jay Kang arrived Friday to serve as a health care volunteer.
"The greed that is prevailing on Wall Street is causing a lot of problems in society today," Kang said.
"That is why I am here to support the protesters."
Occupy Wall Street set up in Zuccotti Park last month with dozens of demonstrators. Since then, thousands more — including various unions such as the Transport Workers Union and the United Federation of Teachers — have joined the movement.
In other affiliated protests Saturday:
Seattle: About 500 people gathered downtown for another day of demonstrations, NBC station KING reported. About 100 officers were present, the Seattle Times said.
According to the Occupy Seattle website, a noon PDT march was moved to 5 p.m. to support an Indigenous people's rally also being held at Westlake, a downtown center.
People started gathering in downtown Seattle this week to protest what they call "corporate greed." Now, state and King County labor councils are calling on union members to join the fight.
State and King County labor councils called on union members to join the fight.
Union leaders say they share many of the same concerns.
"We're fortunate. We have jobs. Unfortunately you can work a full time job in America and still be below the poverty rate," said David Westberg, Engineers Local 609.
Cincinnati: Hundreds rallied downtown Saturday to show solidarity with thousands of protesters who've gathered in New York's financial district, NBC station WLWT reported.
"We're really just trying to show that for one we do know what's going on and to show we're in this for everybody," said Johnathan Spieser, of Occupy Cincinnati.
Demonstrators in Cincinnati gathered at 11 a.m. at Lytle Park. They marched around downtown and in Over-the-Rhine before making their way to Fountain Square, where community leaders, history professors and small business owners spoke.
"This current movement is about truth — letting people know what's going on in our world," said Daniel Dillman, of Occupy Cincinnati. "I'm one of the people affected by layoffs. Corporations are showing record profits but still laying off people."
Organizers have met with police to discuss ways to keep protesters safe and within the bounds of the law. There was extra police presence in the downtown area Saturday to make sure the demonstration doesn't get out of hand.
"It's sometimes hard to get up and get motivated, so we're really excited to have so many people backing this and come together," Spieser said.
Indianapolis: Hundreds of people of all ages marched around the downtown Monument Circle to protest what they see as economic inequality and a government that doesn't listen.
More than 1,000 people gathered on Veterans Memorial Plaza. Most carried signs with sayings like "Stop the war on workers" and "Stop corporate greed."
Mark Gilbert, 52, of Fishers says he joined the protest out of frustration with the economy. Others say they're fed up because the government listens more to corporations than it does voters.
Philadelphia: Hundreds of Occupy Philadelphia demonstrators marched from a makeshift camp outside City Hall to the site of the Liberty Bell on Saturday to dramatize their call for an end to corporate influence on politics.
The protesters marched to the beat of drums and chants such as "This is what democracy looks like" and "Banks got bailed out, we got sold out."
Signs carried by many echoed the message but also talked about issues including university tuition and illegal immigration —and one bore the stark warning "You'll be poor soon too! Join us."
Marcher Goldie Petkov, a 92-year-old Center City resident, told the Philadelphia Inquirer, "They should've been marching months ago."
"Unemployment is overwhelming," the petite retiree said, "and they're spending all this money on wars instead of building bridges, schools and positive things."
Nashville: About 150 people showed up at Centennial Park for an organizational meeting in support of the on-going protests on Wall Street. They told the Nashville Tennessean newspaper that the plan to camp out Saturday night on Legislative Plaza and stay indefinitely.
Jacksonville: About 100 protesters gathered at Hemming Plaza, where Councilman Don Redman called police to inquire whether the group had a permit, the Florida Times-Union reported. He told the group that police won't get involved as long as the protest stays peaceful.
Protesters later marched along sidewalks while chanting "We are the 99 percent."
Chicago: About 100 Occupy Chicago protesters joined with hundreds protesting the war in Afghanistan on its 10th anniversary, NBC station WMAQ reported.
With signs and banners emblazened with "troops home now" and "bring our money home now," several groups gathered near Michigan Avenue and Congress Parkway before marching throughout the area and making a stop outside President Barack Obama's 2012 campaign headquarters. No arrests were reported.
Sacramento, Calif.: The "Occupy Sacramento" movement took on a festival-like atmosphere at Cesar Chavez Park, the Sacramento Bee reported. More than 300 people milled, lounged, sang and waved signs critical of Wall Street and corporate America, the newspaper said. More than a dozen dome tents dotted the park across from City Hall.
Fort Lauderdale, Fla.: Despite stormy weather, hundreds of people showed up at Bryant Park in Lake Worth and Stranahan Park in Fort Lauderdale, the Sun Sentinel reported. to add their voices to the grass-roots chorus echoing from protesters in the Occupy Wall Street movement in recent weeks.
Many came to share opinions, trade information and express outrage as they might on Facebook or Twitter only in a live, face-to-face social network, according to attendee Rachel Shidaker.
Participant Glenn Cernicky told the Sun Sentinel he worried about Social Security.
"We are the 99 percent!" he said. "We're the ones that paid Social Security my whole life and then they're threatening whether to give me my check because of the federal deficit? How dare they?"