Chanting "I can't breathe" and carrying signs saying "black lives matter," thousands of people marched up New York's Fifth Avenue on Saturday as part of a day of protest centered in the nation's capital over the deaths of unarmed black men by police.

Saturday's outpouring of demonstrators followed a series of protests over the last several weeks since grand juries decided against bringing charges against white police officers in the shooting death of Michael Brown in Ferguson, Missouri, and chokehold death of Eric Garner in Staten Island.

Members of the Brown and Garner families joined the Rev. Al Sharpton on Saturday and thousands of others in a march down Washington's Pennsylvania Avenue.

In New York, Rich Alexandro, 47, carried a handmade sign with dozens of names of people who died in encounters with police who were never charged.

"It just seems like the cops are Teflon," Alexandro said. "There's no justice."

Police in Garner's death say he was resisting arrest and was put in a legal arm-hold before he fell to the ground and began complaining "I can't breathe." The officer in Brown's death said that Brown was combative and tried to get his gun; he said he feared for his life when he shot the 18-year-old teenager who some witnesses say was raising his hands apparently in response to the officer's commands.

Donna Carter, 54, marched with her boyfriend, whose teenage son was shot and killed by police in the 1990s while carrying a toy gun.

"It's good to see people of all colors here to say enough is enough," said Carter, who is black. "I'm a parent and every child that's killed feels like my child."

Family members of people killed in New York City police encounters going back decades also were among the demonstrators. They included Iris Baez, whose son Anthony Baez died after he apparently was placed in a chokehold in 1994.

Protesters started in Washington Square Park in Greenwich Village and headed toward midtown. Organizers said they planned to circle back downtown and end the march at police headquarters in lower Manhattan.