Rome, April 17 : The head of the Rome-based UN World Food Program (WFP) has said that the organisation would temporarily halt its humanitarian activities in Sudan, a day after three employees were killed in the country. WFP Executive Director Cindy McCain said on Sunday that she was "appalled and heartbroken" by the deaths, which took place in the Kabkabiya district of the North Darfur state in Sudan, Xinhua news agency reported. In a statement, McCain confirmed reports that the workers were killed "while carrying out their lifesaving duties on the front lines of the global hunger crisis". She also said two other WFP workers were injured in the same attack. The deceased workers were all Sudan nationals, according to media reports. In a separate incident that also took place on Saturday, an aircraft belonging to WFP's Humanitarian Air Service was seriously damaged at Khartoum International Airport, WFP said. "Any loss of life in humanitarian service is unacceptable and I demand immediate steps to guarantee the safety of those who remain," McCain said. "Aid workers are neutral and should never be a target. Threats to our teams make it impossible to operate safely and effectively in the country and carry out WFP's critical work." McCain added that WFP would temporarily halt all its activities in Sudan while reviewing the security situation in the war-torn country. "WFP is committed to assisting the Sudanese people who are facing dire food insecurity," he said. "But we cannot do our lifesaving work if the safety and security of our teams and partners is not guaranteed." Violent clashes erupted on Saturday between the Sudanese Armed Forces (SAF) and the paramilitary Rapid Support Forces (RSF) in Khartoum and other cities, where the two sides traded accusations of initiating the conflict. Sudan's Central Doctors' Committee said that at least 56 civilians had been killed while 595 more have been injured, among them soldiers who are in critical condition. UN Secretary-General Antonio Guterres on Saturday condemned the outbreak of fighting between the two forces, said his spokesman, and called on the two sides to immediately cease hostilities. /IANS