New York: US President Barack Obama on Friday denounced the "despicable" attacks in Dallas in which snipers shot dead five police officers during a protest against police shootings of black men.
"There has been a vicious, calculated and despicable attack on law enforcement," Obama said during a press conference at a NATO summit in Warsaw, adding that the officers were "targeted" by multiple suspects.
The remarks came shortly after 5 transit officers were killed and 11 shot at in downtown Dallas by suspected snipers, during a protest against police shootings in Minnesota and Louisiana.
The officers were killed and several others wounded when snipers opened fire on policemen during protests over two recent fatal cop shootings of black men.
Three suspects - including a woman - have been arrested. One of them has warned negotiators there are "bombs all over" in downtown Texas, police officials said.
Meanwhile, the US aviation authorities have restricted flights over Dallas.
"The suspect that we are negotiating with that has exchanged gunfire with us over the last 45 minutes has told our negotiators that the end is coming, and he is going to hurt and kill more of us, meaning law enforcement. And that there are bombs all over the place in this garage and in downtown," Police Chief David Brown told reporters.
A video of the Dallas shooting has also come to fore.
"So we are being very careful in our tactics so we don't injure our citizens in Dallas as we negotiate further."
Brown had earlier said that the snipers fired upon officers "ambush style." Brown had said three officers were killed, and police issued a tweet later saying a fourth officer had died.
Brown said snipers shot from "elevated positions" during a protest over two recent fatal police shootings.
The gunfire broke out around 8:45 pm yesterday. Live TV video showed protesters marching along a street in downtown when the shots erupted and the crowd scattered, seeking cover.
Hundreds of people had gathered in Union Square Park in Manhattan and took to the streets to protest the recent police-related shootings of two black men.
The protesters yesterday chanted "The people united, never be divided" and "Hands up don't shoot." Police scrambled to keep up with the crowd as the group left the park and marched up Fifth Avenue.
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 white officers. That, too, was captured on a cellphone video.
With AP inputs
