Hundreds of police officers, some in riot gear, descended on Zuccotti Park after midnight Tuesday in a surprise sweep of the Occupy Wall Street headquarters.

It comes just two days ahead of a massive planned demonstration Thursday marking the movement’s two-month anniversary.

Police handed out letters to protesters ordering them to temporarily evacuate the park. Campers were ordered to remove all their tents. Police claimed it was a health issue, and that the park needed to be inspected.

Protesters were told they will be allowed to return to the park in several hours, but without their property, which will be brought to a sanitation garage.

Some protesters have left but a large number have stayed behind. They chanted at police, “Whose park, our park.”

A Bloomberg News report Monday stated that mayors across the country had ordered police to shut down camps allied with the Occupy Wall Street demonstrations, saying they had deteriorated from a protest against income inequality into a backdrop for crime and violence.

In New York City, demonstrators were planning to march in front of the New York Stock Exchange Thursday morning, get on subway trains across all  five boroughs in the afternoon, then rally near City Hall in the evening. Afterward, they were expected to march to area bridges.

Mayor Michael Bloomberg said Monday demonstrators won’t disrupt Wall Street, and that the Stock Exchange will open on time and people will be able to get to work.

Bloomberg has gone back and forth between criticizing Occupy Wall Street and defending it, saying recently that protesters were largely law-abiding and did not bother anyone.

(Source: NBC New York)