Another group of protesters marched from Union Square through the East Village and hopped a barricade onto F.D.R. Drive. Officers standing nearby blocked car traffic as the protesters walked in the street.

The protesters, a diverse and relatively young crowd, held signs saying, “Hands up, don’t shoot,” and “Black Lives Matter.” Around 9 p.m., they began to enter the roadway on the Manhattan Bridge, chanting, “Whose bridge? Our bridge,” and then crossed into Brooklyn.

One protester, Fernando Reals, 37, of the Bronx, carried his 1 ½-year-old son on his shoulder. He said he had also marched during protests over the 2012 death of Trayvon Martin in Florida. “We have to take to the streets to protect our children,” he said as he marched near Union Square.

There were rallies on Tuesday in dozens of cities, including in Ferguson, Washington and Los Angeles. They were in response to a grand jury decision on Monday not to indict Officer Darren Wilson in the shooting death of Michael Brown, 18, in Ferguson in August. In Chicago, protesters had a sit-in outside the mayor’s office, and in Cleveland a crowd blocked a major intersection.