Three police officers shot dead in Baton Rouge, Louisiana, are believed to have been lured to the scene where they would be killed.
The three officers, two from the city's police department and one from the sheriff's office, were ambushed while responding to reports of gunfire yesterday morning.
Two of the officers killed have been named as Montrell Jackson, a 32-year-old who was married and had a four-month-old son, and Matthew Gerald, a 41-year-old father of two.
Mr Jackson, a 10-year veteran of the force, described as a "gentle giant", had written on his Facebook page a few days before he was shot that he was "physically and emotionally" tired and that it was difficult to be a police officer and a black man.
He said that, out of uniform, he was sometimes considered a threat but that, when in uniform, he often received nasty looks, adding: "I swear to God I love this city but I wonder if this city loves me".
Mr Gerald was a married father of two daughters and joined the force just months ago after serving in the Marines and as a Blackhawk crew chief in the Army.
He served three tours of Iraq and was described by an ex-colleague as someone who was "made to serve the people".
Mr Gerald and his wife Dechia celebrated their fourth wedding anniversary just two weeks ago.
The third victim was Brad Garafola, 45, a Sheriff's Deputy with the East Baton Rouge Parish Sheriff's Office who had worked there for 24 years. He had four children, aged between seven and 21.
Three other police officers were shot and injured - 41-year-old Nicholas Tullier, an 18-year veteran of the force, is in critical condition while Bruce Simmons, 51, has non-life-threatening injuries.
The third officer, a 49-year-old also with non-life-threatening injuries, has not yet been named.
The gunman has been named in US media reports as Gavin Eugene Long, a 29-year-old African-American military veteran from Kansas City.
Initially it was thought there were two more suspects at large, but Superintendent Colonel Mike Edmonson said: "There is not an active shooter scenario in Baton Rouge.
"We do believe the person that shot and killed our officers, that he is the person who was shot and killed at the scene."
Law enforcement officers man a road block in Baton Rouge | Photo: PA Images
'Nothing justifies violence'
According to a source quoted by Reuters, there is "reason to believe" that a 911 call was used to lure police to the scene where they would be shot at.
Two "persons of interest" were detained in another town called Addis, which is near Baton Rouge, but they were later released without charge.
Police chiefs appeared at a press conference calling for residents to unite in the face of the violence.
Sheriff Sid Gautreaux said: "To me, this is not so much about gun control as it is about what's in men's hearts.
"And, until we come together as a nation, as a people, to heal as a people, if we don't do that and this madness continues, we will surely perish as a people."
The governor of Louisiana, John Bel Edwards, asked the public to pray for the officers involved and their families, adding: "Rest assured, every resource available to the state of Louisiana will be used to ensure the perpetrators are swiftly brought to justice.
"An attack on one of us is an attack on all of us and the people who carried out the attack, the individuals, they do not represent the people of Baton Rouge or the state of Louisiana or what's best about our country.
"They don't represent the values we stand for."
President Barack Obama said the shooting underscored the danger law enforcement officials faced but that the killer "will not be the last to make us try to turn on each other".
"Regardless of motive, the death of these three brave officers underscores the danger that police across the country confront every single day, and we as a nation have to be loud and clear that nothing justifies violence against law enforcement."
Baton Rouge hit the headlines earlier this month after a black man was controversially shot dead by officers in the city.
The father-of-five who died, Alton Sterling, was laid to rest at a three-hour service in Baton Rouge on Friday.
A wave of nationwide protests followed after Mr Sterling was killed and at one demonstration in Dallas, a gunman opened fire and killed five white police officers.
Following the shooting, the head of the Cleveland Police Union has called on the governor of Ohio to declare a state of emergency and suspend laws allowing people to openly carry firearms during the Republican convention.
On Facebook, presumptive Republican presidential nominee Donald Trump wrote: "How many law enforcement and people have to die because of a lack of leadership in our country? We demand law and order."
Democratic presidential hopeful Hillary Clinton said: "There is no justification for violence, for hate, for attacks on men and women who put their lives on the line every day in service of our families and communities."
