© Mary Altaffer/APA New York City police officer shoves a demonstrator affiliated with the Occupy Wall Street protests as they march through the streets in the Wall Street area, Friday.
Clashes broke out between bottle-throwing demonstrators and police on horses and scooters as Occupy Wall Street protesters marched on the Stock Exchange on Friday, NBC News reported.

At least 10 people were arrested amid what was initially described as a celebratory march, which began when it was revealed the owners of Zuccotti Park - where the protesters had set up camp - had ditched cleanup plans that some claimed were a pretext to evict them.

NBC News reported that police used the scooters to try to force protesters off of the street at several locations on Wall Street and Broadway.

In some cases, police rode scooters directly at people who stopped traffic and refused to move away.

Demonstrators threw bottles and one threw a garbage can at police, according to reporters on the scene.

WNBC reported that at least 10 people had been arrested as police tried to stop about 500 people, with brooms raised in the air, from marching on Wall Street.

NBC News said that one person who had been arrested was injured and bleeding and was taken to the 7th precinct for treatment. NYPD was extending shifts for some officers across the city in response to the situation.

Despite the police's efforts, protesters were gathering at the Stock Exchange, NBC News said.

Elsewhere, police in Seattle earlier confirmed that they had arrested 10 people, while in Denver authorities moved in after protesters ignored a deadline to leave. The Denver Post reported that a "handful" of people out of several hundred who were there when the police operation began were arrested.

Jubilant scenes

There were jubilant scenes earlier in New York when it was revealed the cleanup operation, which some viewed as a showdown with the authorities, would not take place.

Deputy Mayor Cas Holloway said earlier Friday that the park's owner, Brookfield Office Properties, decided late Thursday to delay the cleaning, which had been slated to begin at 7 a.m. ET.

"Brookfield believes they can work out an arrangement with the protesters that will ensure the park remains clean, safe, available for public use and that the situation is respectful of residents and businesses downtown, and we will continue to monitor the situation," Holloway said in an online statement.

NBC News reported that Ric Clark, CEO of Brookfield Global Real Estate, said in an email to Holloway that they "now plan on deferring this work for a few days while we attempt to work out an arrangement with the protesters."

Mayor Michael Bloomberg claimed the company had received threats from lawmakers over the cleanup plan, in his weekly radio appearance, NBC New York reported.

"I think what happened, to my understanding, is that Brookfield got lots of calls from many elected officials, threatening them and saying if you don't stop this, we'll make your life more difficult," he said.

Under the cleanup plan the protesters would have been allowed to return to Zuccotti Park 12 hours later but without sleeping bags and tarps.

However, the activists had feared it was a plot to evict them.

Han Shan, 39, a spokesman for Occupy Wall Street, said Thursday that it was clear to everyone that the cleanup plan was designed to shut down the protest.

"There is a strong commitment to nonviolence, but I know people are going to vigorously resist eviction," he said.

"I think we're going to see a huge number of supporters throughout New York and the surrounding area defend this thing ... I'm hoping that cooler heads will prevail, but I'm not holding my breath," he added.

In New York before it was announced that the cleanup would not take place, protesters scrubbed, mopped and picked up garbage late into the night Thursday in the hope of persuading the owners that the operation was not necessary.

'Thunderdome' cleared

Meantime, in Denver, police moved in after protesters ignored a deadline of 11 p.m. Thursday to leave or face arrest.

Wes Gentry, a city desk reporter at the Denver Post, tweeted that officers began by knocking down tents at the protest in the grounds of the State Capitol.

Organizers of the protest tweeted on the @OccupyDenver account at about 4:45 a.m. local time (6:45 a.m ET) that 150 to 250 people remained in the park.

It had been due to reopen to the public at 5 a.m. local time, but @OccupyDenver said the authorities had told them it was now closed indefinitely. "We can continue from the sidewalks," it said in a tweet.

The Denver Post reported later that the park was cleared by police until only a core group of about 25 people remained at the "thunderdome."

Police then picked some of them up and moved them away from the area, the paper said.

"I don't know why I'm being detained," Patricia Hughes, a nurse, said as she was dragged away on her knees, the Post reported. However, police let her and others go once she was outside a perimeter they had set up.

Some protesters who would not leave were detained, including Vince Lopez, 24, the paper said.

His wife Chelsea Champ-Lopez, 22, cried as he was taken away, saying she would "stay here until I find out what's going on with my husband," the Post reported.

In Seattle, Occupy protesters running a live video feed from their corporate power protest at Seattle's Westlake Park said police made 10 arrests Thursday.

"It has remained non-violent, the energy at Westlake is high but peaceful," the Occupy Seattle group said on its website.

They later said police appeared to have backed off.

The Associated Press and NBC News contributed to this report.