Washington-The episode of violence and murder returned to the U.S with three police officers killed and three others injured, in a shooting in Baton Rouge, Louisiana, according to the head of the local security administration.

A statement released by the city’s office said that one gunman had been killed, and police believed two more shooters may have been at large.

East Baton Rouge Parish Sheriff’s Office spokeswoman Casey Rayborn Hicks stated that the police officers responded to the shooting.

WAFB 9 broadcasted a video showing the police officers’ arrival to the shooting site.

U.S. President Barack Obama condemned the attack, saying there was “no justification” for the violence. The U.S. president added that the perpetrators are cowards.

For his part, Baton Rouge Mayor Kip Holden showed concerns about more potential violent incidents and called for self-restraint.

This incident occurred amid already a tense atmosphere in Louisiana, which witnessed several protests against the police murder of a black man called Elton Sterling in early July.

Another video showing the last minutes of a black man named Filando Castile before being killed by the police in Minnesota went viral and triggered a rage wave.

During demonstrations against police aggression, an armed man killed five police officers in Dallas on July 7 before being shot by the security forces. Killer Micah Johnson, a former soldier, admitted that he wanted to kill white police officers as a revenge.