Alton Sterling was fatally shot in an altercation with police in Baton Rouge on Tuesday. Philando Castile was killed during a traffic stop Wednesday night in the Saint Paul, Minnesota, suburb of Falcon Heights.
In Baton Rouge, Gov. John Bel Edwards led a prayer vigil, delivering remarks with leaders from the community and elected city officials. He said it was important for the state of Louisiana to "have peace at this critical time."
In Washington, D.C., the "March On The White House To End Police Brutality" kicked off at 8 p.m. Participants chanted "Black Lives Matter," while some carried signs that read "Disarm The Police."
At a rally against police brutality in New York City's Union Square, marchers chanted "The whole damn system is guilty," while mentioning the names of other blacks who have died at the hands of police in recent years.
Elsewhere in Manhattan, there were protests in Times Square. Dozens of individuals were arrested, mostly for disorderly conduct.
Rallies took place in other major cities around the U.S. as well. One woman holding a sign in Philadelphia read, "If you're not angry, you're not paying attention." Police took some demonstrators into custody after they were blocking the ramp to Interstate 676, ABC station WPVI in Philadelphia reported.
Protesters ventured into the rain, also blocking traffic on major highways, chanting "No justice, no peace." There, umbrellas were more prevalent than signs.
In Atlanta, hundreds of people also gathered to protest the killings of Castile and Sterling.