Dallas was left reeling a day after five police officers were gunned down by sniper fire, and reaction poured in from around the world.
U.S. President Barack Obama, while in Warsaw for the NATO summit, expressed sympathy for the victims and their families, and said there was "no possible justification" for the killings.
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On social media, condemnation, sadness and frustration were among the myriad of emotions being expressed.
The shooting deaths of Dallas police officers come on the heels of two high-profile fatal shootings of black men earlier this week in the U.S. by police officers.
The family of Alton Sterling, fatally shot by police in Baton Rouge, La., earlier this week said: "Regardless of how angry or upset people may be, resorting to this kind of sickening violence should never happen and simply cannot be tolerated. Members of law enforcement have a very difficult job and the vast majority conduct themselves honorably as they protect and serve our communities."
Black Lives Matter, which in recent years has advocated for peaceful interactions between police and citizens, condemned the Dallas attacks, the same week the organization's Toronto chapter defended its protest at the city's Pride parade against police inclusion in the event.
#BlackLivesMatter advocates dignity, justice and freedom. Not murder.— @Blklivesmatter
The presumptive presidential nominees spoke to the tragic events in Dallas.
Prayers and condolences to all of the families who are so thoroughly devastated by the horrors we are all watching take place in our country— @realDonaldTrump
I mourn for the officers shot while doing their sacred duty to protect peaceful protesters, for their families & all who serve with them. -H— @HillaryClinton
The U.S. attorney general, in addition to saying the government would help with the investigation, expressed her condolences.
This has been a week of profound grief & heartbreaking loss. Our thoughts & condolences go out to the families who have lost loved ones.— @LorettaLynch
Two prominent African-Americans who were part of the civil rights struggles of the 1960s denounced the attacks.
I was beaten bloody by police officers. But I never hated them. I said, 'Thank you for your service.'— @repjohnlewis
Showers of prayers on the families of the deceased police.We must not fight violence with violence. nonviolence is the best way. #Dallas— @RevJJackson
Former U.S. congressman Joe Walsh was not in a conciliatory mood, and said it was time to stand with the men and women in uniform.
It's time 4 patriotic Americans to stand up & stand against all the Cop haters - from Obama to the thugs on the street.— @WalshFreedom
It's way past time.
Orlando's mayor, whose city was rocked by 49 deaths by a gunman at the Pulse nightclub on June 12, released an empathetic statement.
We are stronger when we stand together both as a community and country. #WeStandWithDallas and all cities experiencing such difficult times.— @orlandomayor
Condolences were expressed by international leaders, including the president of the European Council and Canadian Prime Minister Justin Trudeau.
Canadians are shocked by the cowardly attacks against police in Dallas. Our solidarity is with all victims of violence on this tragic week.— @JustinTrudeau
American singer John Legend and TV producer-writer Shonda Rhimes were among the celebrities left stunned and saddened by the events.
Being against cops killing is not equal to being for killing cops. We need peace in our streets.— @johnlegend
As someone with law enforcement in my family, I am just shaking. That does not equal this. Senseless. Horrific. Heartbreaking.— @shondarhimes
A well-known baseball player who is a namesake of the man ID'd by Dallas police as a gunman in Thursday's attack sought to clear up any confusion and express his sorrow.
Here I am today. The other Micah Johnson is not. And for that the world is better. Praying today for this world. pic.twitter.com/Rmp3poly2G— @Micah_Johnson3