Protesters are arrested in Boston, Massachusetts early October 11, 2011. Tensions boiled over early Tuesday in downtown Boston, where police arrested about 100 protesters from the Occupy Boston movement after the group expanded its encampment. [Photo/Agencies]

WASHINGTON - More than 100 Occupy Boston protesters were arrested in US city of Boston early Tuesday, the movement organizer said.

At 1:30 Tuesday morning, hundreds of police "in full riot gear brutally attacked" protesters who gathered on the Rose Kennedy Greenway in downtown Boston, Massachusetts, arresting more than 100 people, the Occupy Boston said in a statement posted on its website.

Police "made no distinction between protesters, medics, or legal observers," it added. Some protesters carrying American flags were pushed to the ground and their flags trampled as the police hauled them away.

The Boston Global reported dozens of sheriff vans and police wagons arrived at the greenway and over 200 officers in uniforms and riot gear surrounded the site.

Protesters chanted "The people united will never be defeated," "This is a peaceful protest," and "The whole world is watching," according to the report.

Protesters of the "Occupy Boston," an offshoot of the "Occupy Wall Street" movement, have set up tents in Dewey Square Park in downtown Boston for weeks and tried on Monday to expand to a larger section of the nearby Rose Kennedy Greenway.

The "Occupy Wall Street" movement appeared to be gaining steam as it entered the fourth week. Starting in New York and spreading almost daily, the protests have reached more than 100 major US cities.

Earlier Monday, an estimated 10,000 union members, students, veterans, and others marched from the Boston Common to Dewey Square, and then to the North Washington Bridge to demand economic reform on Wall Street and the end of special interest influence in Washington, the Occupy Boston said.