Three police officers were shot to death and three others wounded in Baton Rouge, Louisiana on Sunday, in what authorities said was an ambush less than two weeks after a black man was killed by police, sparking nationwide protests. The officers in Baton Rouge were responding to a call of shots fired when they were ambushed by at least one gunman, Baton Rouge Mayor Kip Holden said. One suspect is dead and police are checking the shooting scene with a robot to make sure there are no explosives, Baton Rouge Police spokesman L'Jean Mckneely said. Police told reporters authorities are seeking more than one suspect and said the public should be on the lookout for people dressed in black and carrying long guns. A state police helicopter is seen near the scene where police officers were shot in Baton Rouge, Louisiana, U.S. July 17, 2016.