CHARLOTTE, N.C. Confrontations between protesters and police escalated as the Democratic convention opened Tuesday, with a two-hour standoff uptown followed by scuffling during a nighttime march.

Demonstrators seemed to test police boundaries, taunting officers and blocking a street a few blocks south of the convention site. Police responded with smothering numbers and a bend-but-don’t-break strategy to corral the protesters.

Police arrested 13 people during the day.

Tuesday ended with a night march from Marshall Park, where Occupy Charlotte and other protesters are camped, up Stonewall Street to Tryon. Ranks of police on bicycles stopped the marchers’ turn up Tryon into the center city, some raising batons as protesters and officers briefly scuffled and pushed.

By late Tuesday, hundreds of officers were escorting about 75 protesters on 11th Street back toward the park. No injuries or arrests were immediately reported.

Marcher Brent Lengle said the march had taken on a more aggressive tone than previous protests this week.

“People respond to context. When you put cops in riot gear and welder’s helmets, it’s a different context,” Lengle said. “When people march at night it’s different. There’s more aggression and more frustration that’s built up.”

The number and intensity of the DNC protesters already appear to eclipse those at the rain-soaked Republican convention in Tampa, Fla., last week.

Earlier Tuesday, police arrested 10 undocumented immigrants, reform advocates, who sat down in an uptown intersection and refused to move.

In a separate incident, two other protesters were charged with disrupting a DNC event north of uptown.

Tuesday’s midday stalemate ended when police let about 100 demonstrators walk up a sidewalk toward the Charlotte Convention Center.

“Obama is a war criminal!” protesters yelled at DNC delegates on the center’s steps.

“Four more years!” Obama supporters responded. Many looked surprised and confused as marchers shouted expletives and chanted, “Drone strikes are war crimes, give Obama jail time.”

Marchers headed north on Tryon Street, the heart of uptown, as a moving police roadblock stopped traffic at cross streets.

“We’re just going to let them keep moving,” Charlotte Mecklenburg Police Chief Rodney Monroe said.

The protests forced some delegate buses to the convention to be rerouted, officials later confirmed.

Police gave marchers leeway at times Tuesday, allowing them to march in city streets without a permit. Police also allowed a few marchers to walk wearing helmets and bandana masks – both of which violate a new city ordinance.

“We just want to get where the news cameras are,” protester Anaheim James told Monroe at one point.

“They’re here,” the chief responded, gesturing around.

Laurel Green, an Occupy Charlotte member, gave the police high marks for their handling of the protest.

“It was well done, I thought,” she said. But she said the large police presence could incite trouble with the smaller number of protesters.

“The ratio of police to demonstrators is visually frightening,” she said. “It runs the risk of instigating.”

‘Our nation is in distress’

The standoff began about 1 p.m. Tuesday as about 200 marchers tried to make their way up Stonewall Street and a crowd of about 300 police officers surrounded them. The mass blocked the intersection of Stonewall and Caldwell streets.

Two protesters pitched a tent inside the ordinarily busy intersection.

Some were veterans who spoke out on a variety of issues, including the release of Bradley Manning, the U.S. Army soldier suspected of leaking classified information to the website WikiLeaks. Banks, too, were again a target.

Gathered near the NASCAR Hall of Fame, protesters sang, sat in the street and chanted: “We’re standing here for Manning, we shall not be moved. We’re standing up for freedom and we shall not be moved.”

Police on bicycles surrounded them.

“How do you feel about breaking our Constitutional rights?” one protester yelled at police.

Some marchers carried an upside-down American flag “not out of disrespect but because our nation is in distress,” said Gregory Gifford, 47.

John Penley, 60, an Asheville veteran and an organizer of the march, wrapped an American flag around himself. He was arrested and charged with breaching a police line.

Demonstrators and anti-abortion protesters hurled insults at each other near the convention center. Activists chanted “free Bradley Manning” as abortion opponents held up signs with pictures of aborted fetuses.

Protesters ignored the nearby “free speech zone,” a fenced enclosure near the convention center that critics have derided as a cage. A handful walked to the edge of the zone and danced the “Hokey Pokey,” singing, “You do the Hokey Pokey and kiss your rights goodbye. That’s what it’s all about!”

Asked whether events were going as expected, city attorney Robert Hagemann stood in the empty free speech zone and replied: “It is what it is. What’s working out is that the police are handling this very well.”

Immigrants arrested

Later Tuesday, 10 undocumented immigrants were arrested after sitting down in an uptown intersection and refusing police orders to disperse. Jail records show the majority of those arrested had bonded out of the Mecklenburg jail early Wednesday.

The activists are part of the “Undocubus,” a group of about 50 undocumented immigrants traveling from Phoenix to Charlotte to argue for immigration reform during the DNC.

“We are demanding from the president to stop the deportations and separation of families,” said Gerrardo Torres of Chicago.

Because Mecklenburg County participates in the federal 287 (g) program, which screens all arrested suspects for immigration status, all those arrested Tuesday stand the chance of being deported. They said they were prepared to risk that to make their voices heard.

Those arrested sat down in the intersection of Fifth and College streets, one block from the convention site at Time Warner Cable Arena, as delegates arrived to go through a nearby security checkpoint.

In heavy rain they chanted, “Undocumented and unafraid,” partially blocking the intersection as police watched. The group also chanted, “Obama, listen, we’re in this fight,” in Spanish, holding signs that said “Undocumented” over their heads.

Although President Barack Obama has stayed deportations for many young immigrants in the country illegally, the recent federal exemption doesn’t apply to all, including those older than 30.

After about 30 minutes, police told the group to disperse. More warnings to leave came about 10 minutes later because they were impeding traffic. In Spanish, the immigrants chanted, “We will not be moved.”

Police led them away to waiting prisoner transport vans about 5:10 p.m.

Corporations targeted

Corporate influence on politics and government drew the ire of protesters throughout the day.

Tuesday morning, two activists were charged after disrupting an Atlantic/National Journal energy panel, demanding an end to corporate political contributions. Police confiscated a solution of baking soda, vinegar and green food dye meant to depict the corrosive impact of corporate donations on politics.

Paul G. Davis, 43, was charged with disorderly conduct and dispersal of a noxious substance. Dylan W. Wrynn, 42, was charged with disorderly conduct.

Late that afternoon, as conventioneers lined up at the College and Fifth checkpoint, a dozen members of the women’s antiwar group Code Pink protested the influence of large corporations in government.

Bust up big banks, they shouted, throwing bras into the air. The women sang a remixed version of “When the Saints Go Marching In” to encourage government to dismantle banks and shift money to local credit unions.

Their voices echoed off the walls of the Ritz Carlton hotel and Hearst Tower, but it was unclear whether they were heard by conventiongoers scurrying to find shelter from the rain. Staff writers Bruce Henderson, Caroline McMillan, Gavin Off, Cleve Wootson, Fred Clasen-Kelly, Joe DePriest, Lindsay Ruebens, Ames Alexander and April Bethea contributed.