Johannesburg - President Jacob Zuma on Sunday condemned the killing of four police officers and one metro police officer in the past week."Police are the buffer between the community and criminals and we should all work together to support the police in their work," he said in a statement."We also urge our law enforcement officers to defend themselves against criminals within the confines of the law. We salute all law enforcement officers who work diligently under difficult conditions to rid our country of crime."Zuma sent condolences to the families of the five men."Our hearts go out to the families who are going through pain because of heartless criminals who have no respect for human life," he said.On Monday, a 60-year-old Johannesburg metro police officer was on his way to withdraw cash at an ATM in a mall in Rosettenville just before 15:00, when he came across two men robbing a cash-in-transit security guard carrying a case of money.During a scuffle with one of the robbers he was shot once, and twice more after he fell to the ground, Chief Superintendent Wayne Minnaar said.On Wednesday, a 36-year-old police officer was killed during a shoot-out with robbers at the Vosloorus Crossing mall.On the same day, in the Western Cape, Petrus Holz, 50, member of the Hawks, was stabbed to death when he stopped on the N2 to inspect damage to his car after he drove over debris in the road.On Thursday morning, a 35-year-old officer was shot while responding to a business robbery in Sekampane, Temba, north of Pretoria, Gauteng police spokesperson Lieutenant Colonel Lungelo Dlamini said. He died on arrival at a local hospital.On Friday, a 34-year-old police constable was shot and killed in Jeppestown, Johannesburg, when he and a colleague went to investigate a group of men sitting in a parked minibus taxi.Deputy Police Minister Maggie Sotyu said 52 police officers had been killed since January, compared to 47 for the same period last year.