A former Marine dressed in black and carrying extra ammunition shot and killed three Baton Rouge law enforcement officers Sunday, less than two weeks after a black man was fatally shot by police here in a confrontation that sparked nightly protests that reverberated nationwide.

Three other officers were wounded, one critically. Police said the gunman was killed at the scene.

The shooting less than a mile from police headquarters added to the tensions across the country between the black community and police. Just days earlier, one of the slain officers had posted an emotional Facebook message about the challenges of police work in the current environment.

President Barack Obama urged Americans to tamp down inflammatory words and actions.

“We don’t need careless accusations thrown around to score political points or to advance an agenda. We need to temper our words and open our hearts … all of us,” Obama said.

The gunman was identified as Gavin Long of Kansas City, who turned 29 on Sunday.

Long, who was black, served in the Marines from 2005 to 2010, reaching the rank of sergeant. He deployed to Iraq from June 2008 to January 2009, according to military records.

Although he was believed to be the only person who fired at officers, authorities were investigating whether he had some kind of help.

“We are not ready to say he acted alone,” state police spokesman Major Doug Cain said. Two “persons of interest” were detained for questioning in the nearby town of Addis. They were later released without any charges being filed. (AP)