President Barack Obama assured a shocked America Saturday that the black extremist who shot dead five cops in Dallas was a lone wolf -- and that the country can overcome its racial divisions, as the groundswell of anger over police brutality surged on.
Thousands of protesters marched in US cities overnight to demand justice for two African-Americans whose fatal shooting by police triggered the rampage in Dallas by an army vet bent on killing white officers in revenge.
The nightmare scenes in Texas -- where the ambush turned a peaceful protest to horror -- left many fearing a new, dark chapter in America's troubled race relations.
But as Dallas honored its slain officers, Obama sought to cut short that narrative -- saying Americans of all backgrounds were united in grief both at the recent fatal shooting of African-Americans and the murders in Dallas.
"I firmly believe that America is not as divided as some have suggested," Obama told a press conference at a NATO summit in Warsaw. "There is sorrow, there is anger, there is confusion... but there is unity."
"The demented individual who carried out the attacks in Dallas, he's no more representative of African-Americans than the shooter in Charleston was representative of white Americans," he said, referring to the murder of nine black worshippers at a church in South Carolina last year.
Dallas officials have now said they are certain the atrocity was the work of a lone shooter -- 25-year-old Micah Johnson, killed in a showdown with police -- and not a group of co-conspirators as initially feared.
"We believe now that the city is safe," Mayor Mike Rawlings told a news conference late Friday.
The Black Lives Matter activist movement which is spearheading months of nationwide protests over police brutality has demanded an end to violence -- not an escalation.
There were nasty scenes in Phoenix, Arizona where police used pepper spray to disperse stone-throwing protesters. And in Rochester, New York, 74 people were arrested over a sit-in protest blocking a street.
But elsewhere -- from Atlanta to Houston, New Orleans, Detroit or Baltimore -- the marches passed off without trouble.
Fresh protests were planned Saturday in at least half a dozen cities including Seattle, Indianapolis and what was dubbed a "Weekend of Rage" in Philadelphia.
Obama is to visit Dallas early next week in a bid to appease tensions and chart a way forward following the Dallas ambush, and the police shootings of Alton Sterling in Louisiana and Philando Castile in Minnesota, captured in now-viral video footage.
Leaders from across the US spectrum have spoken out in a spirit of appeasement after a week of violence that graphically highlighted America's racial challenges.
They include prominent members of the Republican Party, which has often jumped to the defense of law enforcement in the face of accusations of racial bias.
"It is more dangerous to be black in America," Newt Gingrich, a Republican former House speaker tipped as a possible White House running mate for Donald Trump, said in an interview on Facebook Live.
"Sometimes it's difficult for whites to appreciate how real that is. It's an everyday danger."
Republican Florida Senator Marco Rubio had a similar message, issuing a statement saying: "Those of us who are not African American will never fully understand the experience of being black in America."
"As Americans, we are wounded by all of these deaths," Vice President Joe Biden said Saturday, echoing Obama's message that black lives matter -- and so do "blue" lives, those of police officers.
"It's on all of us to stand up, to speak out about disparities in our criminal justice system -- just as it's on all of us to stand up for the police who protect us in our communities every day," he said.
The Dallas ambush marked the single biggest loss of life for law enforcement in the United States since the September 11, 2001 terror attacks.
Police were set further on edge as it emerged several officers had been targeted across the country from individuals apparently angered at the recent fatal shootings.
In Tennessee Thursday a man opened fire on a hotel and a highway, killing a woman, grazing a police officer with a bullet and wounding several others.
The Tennessee Bureau of Investigation said the gunman "may have targeted individuals and officers after being troubled by recent incidents involving African-Americans and law enforcement officers."
And in Racine, Wisconsin, police said a 43-year-old man was arrested over threatening social media posts that read: "I encourage every Black man in America to strap up... I encourage every white officer to kiss there (sic) love ones goodbye."
Described to police as a "loner," the Dallas gunman served as a US Army reservist for six years, including a tour of duty in Afghanistan and had no criminal record.
While the White House has ruled out any link between Johnson and known "terrorist organizations," the gunman's Facebook page ties him to several radical black movements listed as hate groups.
He told negotiators before he died that he wanted to kill white cops in retaliation for the fatal police shootings in Louisiana and Minnesota.
Police found bomb-making materials and a weapons cache at his home and were scouring his journal and social media posts to understand what drove him to mass murder.