Boston police moved in and began arresting scores of Occupy Boston protesters who refused to leave a large part of the Rose Fitzgerald Kennedy Greenway early this morning.
At 1:20 a.m., the first riot police officers lined up on Atlantic Avenue. Minutes later, dozens of sheriff vans and police wagons arrived and over 200 officers in uniforms and riot gear surrounded the Greenway.
Police Superintendent William Evans and Commissioner Edward F. Davis watched from across the street. Evans gave the crowd two minutes to disperse from the park, warning that they would be locked up if they did not comply.
The crowd of protesters, energized by the sudden appearance of the Boston and Transit police officers, chanted, ‘‘The people united will never be defeated,’’ “This is a peaceful protest,” and “the whole world is watching.’’
About 10 minutes later, the first officers entered the park and surrounded the group. Evans, using a loudspeaker, gave one more warning and then each protester was individually put on his or her stomach, cable-tied, and dragged off as others tore down tents and arrested and detained people on the fringe of the park.
About 100 people were arrested, Davis said. One police officer was hit in the face.
According to police, no protesters or police were injured.
A lot of the protesters retreated from the Greenway to Dewey Square when the police arrived.
Police had earlier warned the about 1,000 protesters to leave the Greenway area, where they had settled hours before, and relocate to Dewey Square or a small, adjacent strip of the Greenway.
Officials do not want the protesters, who originally settled in Dewey Square, to occupy the space across Congress Street on the Greenway because it recently underwent a renovation project where expensive improvements were added, according to Elaine Driscoll, police spokeswoman.
Prior to moving in on the protesters, police had closed all the streets in the area.
Also, the protesters’ chants stopped as their companions were being lead off by police. Some protesters would then yell out the phone number of a lawyer group that would defend them if they were charged.
As the officers lined up this morning, some members of the crowd shouted, “you don’t have to do this” and “who do you protect, who do you serve?”
At one point, eight to 10 officers in riot gear tackled and cable-tagged one protester who appeared to be resisting. When the chanting stopped an eerie silence came over the park except for the occasional heckling from remaining members of the crowd gathered across the street.
Some in the crown also chanted, “down with Menino.”
John Nilles, 74, a Marine from Medford who served in Vietnam and is a member of the group, Veterans for Peace, said he was knocked down during the arrests.
He believes he did not get arrested in the chaos because he got knocked down, and banged up his knee.
“I have absolutely no use for police anymore,” he said. “I don’t know what I’m going to do.”
He talked about how it reminded him of the 1960s. “This is not the world I intended to come back to,” he said in reference to Vietnam.
Occupy Boston, in a statement Monday night, said it answered the police warning by issuing a call “for any and all people to join the occupation as soon as possible.”
“From the beginning, occupiers have worked tirelessly to maintain a positive working relationship with city officials. Today’s threats by the Boston Police Department represent a sudden shift away from that dialogue,” the statement said.
Mayor Thomas M. Menino’s office said the city would not clear protesters from Dewey Square, however, and police did not move on those demonstrators.
After the police warning, some protesters said they were prepared to be arrested.
“I think we will stand and be arrested,” said Nadeem Mazen, who called himself a part of Occupy Boston, speaking in front of the movement’s media tent.
Earlier, hundreds of protesters, mainly college students, marched from Boston Common to Dewey Square in support of Occupy Boston and to demand fundamental and lasting economic and political reform, Occupy Boston said in its statement.
Two restaurant workers in the financial district said they saw a convoy of police vehicles, wagons, unmarked cars, and motorcycles pass by several hours ago with more than 200 officers. The convoy was driving away from the Greenway toward another financial district building where protesters believe they were staging for the late-night confrontation.
Tensions and new questions arose late Monday night when, at about 11:15, police issued written instructions and expectations of the growing group of protesters if officers demand that they disperse.
The notice informed the group of laws against trespassing on a new patch of the Greenway -- bordered by Congress Street, Atlantic Avenue, Pearl Street, and Purchase Street -- where tents have sprung up since about 4 p.m, and is also private property.
In a section titled, “What Occupy Boston Participants can expect from the BPD,” the statement said officers will “arrest those knowingly in violation of the law if necessary,” and that they will “conduct themselves in a professional, respectful and proportional manner.”
Police said they will use video to identify participants deemed to be breaking trespassing and unlawful assembly laws, which could apply to the demonstrators, who planned to encircle the camp, lock arms, and resist ejection.
Police said that if five armed people, or 10 unarmed people, are found to be unlawfully assembled, “police can demand that they immediately and peaceably disperse.”
The notice also included the potential legal consequence for unlawful assembly (up to one year in prison and up to a $500 fine) and trespassing (30 days in jail and $100 fine).
At both the Greenway and at Dewey Square, “medical tents” were set up with large red crosses taped on them and volunteers claiming to be EMTs, paramedics, and others trained in first aid with red crosses taped to their backs and shoulders.
Protesters have held up signs with the phone number of a lawyers’ group in Boston in case people are arrested, and the ACLU has passed out cards with instructions on how to deal with police if someone is stopped or arrested.
Globe Correspondents Matt Byrne and Martha Shanahan and Matt Lee of the Globe Staff contributed to this report.
John M. Guilfoil can be reached at firstname.lastname@example.org. Follow him on Twitter @globe_guilfoil. Derek J. Anderson can be reached at email@example.com.