Tributes to civil rights leader Martin Luther King Jr. were held across the United States on Monday, with observers linking the federal holiday to a rallying cry in recent protests over police brutality: "Black lives matter."
King's 1960s dream of racial equality was being viewed through a lens focused on the deaths of unarmed black men after confrontations with police, including Eric Garner, who died in July after being put in a chokehold in New York City, and Michael Brown, shot in Ferguson, Missouri, in August.
More than 60 people demonstrating against police brutality were arrested after blocking traffic on the San Mateo-Hayward Bridge, a major thoroughfare in the San Francisco Bay Area, said California Highway Patrol Officer Damian Cistaro.
Another 19 people were arrested by Seattle police after protesters blocked a major artery, causing traffic delays.
More than 1,800 people pressed into a King commemoration service at the Ebenezer Baptist Church in Atlanta, where King once preached, some holding signs with his famous quote "I am a man," others with placards reading "I can't breathe" in Garner's memory and "Hands up! Don't shoot!" to honor Brown.
"We look at the yellow crime scene tape that's wrapped around America now and we know that we have a lot of work still to do," Gwendoyln Boyd, president of Alabama State University, told the crowd that responded with an earsplitting "Amen!"
'Reclaiming Martin Luther King'
About 400 protesters blocked traffic in New York City as they walked about 60 blocks from Harlem to near the United Nations, chanting "Black lives matter!" as King's speeches blared from loudspeakers.
"This march is about reclaiming Martin Luther King. He was a radical organizer - he's been arrested, he believed in non-violence, but he was also disruptive," said Linda Sarsour, spokesperson for the Justice League NYC, which organised the #Dream4Justice March.
Hours before an evening vigil on the Staten Island street where Garner died, his family placed wreaths on the Brooklyn street where two uniformed officers were ambushed in December by a gunman claiming to avenge the deaths of Garner and Brown.
"This holiday should also represent that we are unequivocally against the shedding of innocent blood," said the Rev. Al Sharpton, who accompanied Garner's widow, mother and children as they laid down arrangements of blue hyacinths and white roses.
Demonstrations in other US cities included 1,500 protesters against police brutality in Oakland, California, said Oakland Police Officer Johnna Watson. There were no arrests.
President Barack Obama, the nation's first African-American president, took a more traditional approach to honoring King, spending the day working with his family and other children on a literacy project at a Washington charity.
Obama has shied away from race-related activism, but after a grand jury failed to indict a white officer in Brown's death, he spoke out against what he called the "deep distrust" between law enforcement and black Americans, vowing to use his last two years in office to improve community policing and trust between the groups.