Anti-capitalist demonstrators who were evicted from a New York park earlier this week are promising to “fight back” on Thursday with a rally to commemorate the two month anniversary of the Occupy Wall Street movement.

The protesters say they plan to shut down the city's financial district with a morning rally at the New York Stock Exchange, before taking the protest to the city's subways and major bridges later in the day.

City officials say extra police will be on hand for the protest, which is set to begin at 12:00 UTC. Authorities warn that the rally could disrupt the morning commute.

New York Deputy Mayor Howard Wolfson told reporters Wednesday the city was preparing for a crowd of “tens of thousands.”

The rally is seen as a key test of strength for the loosely-organized movement, which experienced a setback on Tuesday after police dismantled their two-month-old “tent city” from Lower Manhattan's Zuccotti Park.

The demonstrators later filed a motion seeking to be allowed back into the park with their tents and sleeping bags, but a judge ruled that the protester's constitutional right to free speech was not violated by the park's ban on sleeping.

New York Mayor Michael Bloomberg said he agrees with the judge's decision that free speech does not include the right to “endanger the public or infringe on the rights of others by taking over a public space.”

Since September, several hundred protesters had camped out at Zuccotti Park, which had become the epicenter for the nascent anti-capitalist protest movement.

Thursday's protest comes amid rising tension nationwide between protesters and police, who have recently cleared similar encampments in areas such as Oakland, California and Portland, Oregon.

The Occupy Wall Street website says protests will also be held Thursday in the U.S. cities of Atlanta, Detroit, Portland and Washington DC. It also says rallies will take place in Belgium, Germany, and Spain.