The Occupy Wall Street protest picked up more momentum Thursday, with supporters saying it has spread to hundreds of cities worldwide.

The protest even inspired questions at U.S. President Barack Obama’s news conference at the White House, where the president said the demonstrators are expressing the frustrations of the American public.

The website Occupy Together said the movement had gained supporters in 670 cities and Americans continued to post hundreds of photos to the Tumblr blog We Are The 99 Percent, contrasting themselves with the wealthiest one per cent of Americans.

And activists have been showing solidarity with the movement in many U.S. cities, including Los Angeles, Philadelphia, Boston, Seattle, Austin, Texas and Providence, R.I.

In Los Angeles, police arrested about 11 anti-Wall Street demonstrators who entered a Bank of America during a march by hundreds of union members, students, activists and others among downtown highrises containing offices of banks and other financial businesses.

Police Cmdr. Blake Chow said the group sat down in the lobby and refused requests by the manager and employees to leave. Police were then called.

Demonstrators have also been camping out at Los Angeles City Hall for the past week and say they may continue to do so through the winter.

Protests are planned in Canadian cities such as Vancouver, Montreal and Calgary. On Oct. 15, a group plans on staging a sit-in in Toronto’s financial district.

The protests began on September 17 when a few dozen demonstrators tried to pitch tents in front of the New York Stock Exchange but were turned out by police.

Since then, hundreds have gathered at their base at Zuccotti Park, not far from the exchange.

The protestors have many causes, but much of the focus is on Wall Street practices and economic inequality.

The number of demonstrators at the Occupy Wall Street protest grew from a few dozen to hundreds at Zuccotti Park Thursday in lower Manhattan. Bebeto Matthews/Associated Press

Obama acknowledged that, saying the government must ensure the financial sector remains healthy, but not by allowing Wall Street banks to compete “on the basis of hidden fees, deceptive practices or derivative cocktails that nobody understands and that expose the entire economy to enormous risks."

Among some protesters, reaction to Obama's acknowledgment was less than enthusiastic.

"His message is that he's sticking to the party line, which is, `We are taking care of the situation.'

But he's not proposing any solutions," said Thorin Caristo, a 37-year-old antique store owner from Plainfield, Conn.

On Wednesday, thousands of protestors, including many from unions, marched through lower Manhattan.

Labour leaders pledged continued support with manpower and donations of goods and services.

"The great thing about Occupy Wall Street is that they have brought the focus of the entire country on the middle-class majority," said George Aldro, 62, a member of Local 2325 of the United Auto Workers, as he carried the union's blue flag over his shoulder through lower Manhattan.

"We're in it together, and we're in it for the long haul."

Activists, shown Wednesday, have been camped out in front of Los Angeles City Hall in solidarity with the Occupy Wall Street protest. Frederic J. Brown/AFP/Getty

The escalation in support for the movement came a day before the government’s release of its latest U.S. employment report, which was widely expected to show the jobless rate remains at 9.1 per cent for a third straight month.

Nearly one-third of the unemployed — nearly 4.5 million people — have had no job for a year or more, a record high.

Several Democratic lawmakers have expressed support for the protesters, but some Republican presidential candidates have rebuked them.

Herman Cain called the activists "un-American" Wednesday at a book signing in St. Petersburg, Fla.

"They're basically saying that somehow the government is supposed to take from those that have succeeded and give to those who want to protest," the former pizza-company executive said.

"That's not the way America was built."

On Tuesday, CBS reported that former Massachusetts Gov. Mitt Romney called the protest "class warfare" at an appearance at a Florida retirement community.

With files from The Associated Press