President Barack Obama shared his condolences and horror over Thursday night's fatal shooting of five law enforcement officers in Dallas following a peaceful protest against police violence.

He characterized the attack as a "vicious, calculated, despicable attack on law enforcement."

According to police, 11 people were injured when snipers opened fire on officers around 9 p.m. local time as a demonstration came to a close Thursday night. Five of the officers subsequently died of their wounds, according to the Dallas Police Department.

At least one civilian was also injured.

"Police in Dallas were on duty, doing their jobs keeping people safe during peaceful protests," Obama said in a news conference Friday morning in Warsaw, Poland, where he was for a NATO summit. "I believe I speak for every single American when I say that we are horrified by these events and that we stand behind (the police)."

In a news conference early Friday, Dallas Police Chief David O. Brown said three suspects were in custody in relation to the shooting. Two of them were apprehended after they were seen throwing camouflage bags into the back of a car and speeding away from the scene. No additional details were available on the connection between the third suspect, a woman, and the shooting.

Another person suspected in the shooting died following a shootout with a SWAT team, according to KXAS.

"We will learn more, undoubtedly, about their twisted motivations but let's be honest, there's no possible justification," Obama said. "Justice will be done."

On Thursday, Obama addressed recent shootings by police officers which have sparked controversy and protests nationwide.

On Wednesday, a Minnesota officer fatally shot Philando Castile while he was in a car with a woman and a child in a St. Paul suburb. The aftermath of the shooting was purportedly livestreamed in a widely shared Facebook video.

A day earlier, Alton Sterling was shot in Louisiana after being pinned to the pavement by two officers. That, too, was captured on a cellphone video.

"Our police have an extraordinarily difficult job, and the vast majority of them do their job in outstanding fashion," Obama said. "(Speaking Thursday) I also indicated the degree to which we need to be supportive of those officers who do their job each and every day -- protecting us and protecting our communities. Today is a wrenching reminder of the sacrifices that they make for us."

He added that it will be necessary to again review gun laws in America in the wake of the shooting.

"When people are armed with powerful weapons, unfortunately it makes attacks like these more deadly and more tragic," he said. "In the days ahead we're going to have to consider those realities as well."

He asked for Americans to keep law enforcement officers and the people of Dallas in their prayers.

"Keep them in your thoughts and, as a nation, let's remember to express our profound gratitude to our men and women in blue not just today, but everyday," he said.