Washington (AFP) - Three police officers were killed and three wounded in a shooting in the Louisiana capital of Baton Rouge on Sunday, with at least two suspects at large, amid a resurgence of violence involving law enforcement.
The shooting took place in a city scarred by high racial tensions and numerous protests against police brutality since the death earlier this month of Alton Sterling, a black man shot at point-blank range by an officer.
"One suspect is dead, law enforcement believes two others may be at large," the East Baton Rouge sheriff's office said in a statement Sunday.
The shooting took place along a highway around 9:00 am (1400 GMT), the statement added, though the exact circumstances remained unclear.
It appears the incident began before police officers arrived on scene.
"It's my understanding that they (the officers) had responded to an initial shooting incident," Casey Rayborn Hicks, public affairs officer for the sheriff's office, told local WAFB television.
Witness Brady Vancel told the station that he saw what may have been gang members shooting at each other before police arrived.
"This has nothing to do with any situation," he said, referring to controversies surrounding a series of high-profile shootings involving police -- including the killings July 7 of five Dallas police officers -- that have shocked the country over the last several weeks.
One of those killed was Sterling, who was shot two days before the Dallas attack.
The shootings helped expose deep fault lines through society, reviving long-running debates about racial prejudice and an epidemic of gun violence.
- 'Cowardly' -
President Barack Obama, who has had to address multiple mass shooting tragedies during his term, condemned the Baton Rouge shooting as "cowardly" and demanded an end to such violence. He is due to make an address on the violence at the White House at 4:30 pm (2030 GMT).
"For the second time in two weeks, police officers who put their lives on the line for ours every day were doing their job when they were killed in a cowardly and reprehensible assault," Obama said in a statement.
"These are attacks on public servants, on the rule of law and on civilized society, and they have to stop."
The five police officers in Dallas were killed by a gunman during a demonstration triggered by the fatal police shooting of Sterling and another African-American man in Minnesota whose dying moments were captured in shocking video footage that went viral online.
The first African American president of the United States, Obama has made repeated calls for racial unity.
"We may not yet know the motives for this attack, but I want to be clear: there is no justification for violence against law enforcement. None," Obama said.
"These attacks are the work of cowards who speak for no one. They right no wrongs. They advance no causes."
Obama pledged the federal government's full support in the investigation of the incident.
"There is no place in the United States for such appalling violence," his Attorney General Loretta Lynch said.
Donald Trump, the presumptive Republican presidential nominee, took to Twitter to say: "We are TRYING to fight ISIS, and now our own people are killing our police. Our country is divided and out of control. The world is watching."
- Wearing all black -
During Sunday's shooting, Vancel said he saw two men running away and a third lying motionless on the ground. At least one was carrying what appeared to be an AR-15 automatic rifle amid the sound of gunfire.
The races of the shooters and the police officers involved were not immediately clear.
WAFB broadcast video footage of police responding to the scene near a gasoline station. Multiple shots could be heard as civilian cars quickly backed away.
However, there were conflicting reports about the shooting, with WBRZ television reporting a witness describing a man dressed in black, his face covered, shooting indiscriminately.
Police are looking for the two suspected surviving shooters.
"We're not sure of anything right now," Baton Rouge police spokesman L'Jean McNeely told reporters near the scene, urging local residents to be on alert for the suspects.
The injured police officers were reported to be in critical condition, undergoing treatment at a nearby trauma center.
Video posted online showed a SWAT team en route to the scene.
- Unspeakable and unjustified -
"This is an unspeakable and unjustified attack on all of us at a time when we need unity and healing," Louisiana Governor John Bel Edwards said in a statement.
"Rest assured, every resource available to the state of Louisiana will be used to ensure the perpetrators are swiftly brought to justice."
Last week, police arrested more than 100 protesters taking part in a demonstration against police brutality in Baton Rouge under the banner of the Black Lives Matter movement.
Sunday's shootings also play into a debate about gun control in a country in which firearms killed some 13,440 people last year, according to the Gun Violence Archive.
Last month, Democratic lawmakers, pushing for tougher gun-control laws after a massacre in a Florida gay nightclub killed 49 people, staged a virtually unprecedented 24-hour sit-in in Congress after Republicans refused to allow a vote on two widely supported measures