NEW YORK (AP) -- About 100 protesters have been marching through midtown Manhattan, tying up evening rush-hour traffic.

A man, left, holds his hands up as New York City Police officers secure a street near Rockefeller Center during a protest after it was announced that the police officer involved in the death of Eric Garner is not being indicted.(AP Photo/Julio Cortez)

They were heading from Times Square in the direction of Rockefeller Center, where a big tree-lighting ceremony is being held.

The tree lighting comes just hours after a grand jury decided not to indict a police officer in a man's videotaped chokehold death. Mayor Bill de Blasio canceled his planned appearance at the tree lighting to meet with elected officials and activists on Staten Island while citywide protests started to gather steam.

The decision in Staten Island not to indict Officer Daniel Pantaleo threatened to add to the tensions that have simmered in the city since the July 17 death of Eric Garner – a case that sparked outrage and drew comparisons to the fatal police shooting of 18-year-old Michael Brown in Ferguson, Missouri.

Protesters chanted "Black lives matter" as dozens of police officers, some on scooters, looked on.

Earlier, Times Square protester Meredith Reitman of Queens said she feels "horrified" and cried when she learned of the grand jury's decision.

Reitman, who is white, carried a sign that said "white silence equals white consent."

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