There was dismay, shock and fury Friday at the deadly police ambush in Dallas — an unfolding national tragedy that cut across two burning issues of gun control and the use of deadly force against black suspects by law enforcement.
Snipers shot 12 officers who were policing a protest march organized in the wake of the fatal police shooting of Minnesota school kitchen supervisor Philando Castile. Five of the Dallas police officers were killed.
Gabby Giffords, the ex-congresswoman who became an outspoken advocate for gun control after surviving being shot in the head in 2011, tweeted that she was "heartbroken" by the killings.
President Barack Obama, who was in Poland for a NATO meeting, condemned the "vicious, callous and despicable attack."
"I believe I speak for every single American when I say that we are horrified over these events and that we stand united with the people and the police department in Dallas," the president told reporters. "We also know that, when people are armed with powerful weapons, unfortunately that makes attacks like these more deadly and more tragic."
As much of downtown Dallas remained on lockdown early Friday, Texas senator and former Republican presidential hopeful Ted Cruz tweeted his support for police.
Donald Trump tweeted "prayers and condolences" to the families "who are so thoroughly devastated by the horrors we are all watching take place in our country."
His Democratic rival Hillary Clinton, meanwhile, said on twitter that she "mourned for the officers shot while doing their sacred duty to protect peaceful protesters, for their families and all who serve with them."
Clinton's rival in the Democratic primary Bernie Sanders, also tweeted his shock.
Orlando Mayor Buddy Dyer, whose city is still recovering from the mass shooting in that city's Pulse nightclub that left 49 dead in that city on June 12, also expressed his support.
Former House Speaker Newt Gingrich — a rumored potential vice presidential choice for Trump — said the shooting should be a "wake-up call" and criticized the president.
"We're in the eighth year of a president who could have brought us together," Gingrich said on Fox News. "A president who could have worked in the African-Americans community to make people feel better about themselves. A president who could have offered visionary changes in the policies that have failed for the last 50 years. They don't the all of that."
Massachusetts Sen. Elizabeth Warren — a rumored potential vice presidential pick for Clinton — pushed back against the violence that sparked the protests and the violence that occurred there, while dismissing the more divisive reactions.
Former president and former Texas Gov. George W. Bush released a statement saying he and wife Laura were "heartbroken" over the deaths in their state.
"Murdering the innocent is always evil, never more so than when the lives taken belong to those who protect our families and communities," the former president said.
The National Rifle Association — which remained largely silent over the protest-sparking deaths of two men who were armed and later killed by police during routine traffic stops — released a statement mourning those lost in Dallas.
"I want to express the deep anguish all of us feel for the heroic Dallas law enforcement officers who were killed and wounded, as well as to those who so bravely ran toward danger to defend the city and the people of Dallas," NRA executive vice president and CEO Wayne LaPierre said in a statement.
California Attorney General Kamala Harris said the shootings in Dallas were "a grave reminder of the dangers our law enforcement officers face each day in service of their communities."
"I pray for the officers who lost their lives tonight, for their grieving families and our law enforcement brothers and sisters in Dallas," she added in a statement.
As graphic video of what appeared to be the execution-style shooting of police was shared online, some also lashed out in anger.
Former Republican Congressman from Illinois Joe Walsh sent a slew of furious tweets directed at Obama and the Black Lives Matter movement, which has organized demonstrations to draw attention to the deaths of people of color at the hands of police.
The radio host also tweeted that he had not been calling for violence "against Obama or anyone" after reportedly deleting an inflammatory post.
"Obama's words and BLM's deeds have gotten cops killed," he said. "Time for us to defend our cops."