UNITED NATIONS - A sewage backup caused bad smell at the United Nations on Tuesday, forcing diplomats and their staff to evacuate a part of the huge UN complex where the Security Council and General Assembly are located. UN Spokesman Farhan Haq said the evacuation was a precautionary measure after a strange smell was noticed in parts of the U.N. secretariat building. He said the odor was due to sewage backup possibly caused by high tides in the nearby East River. There were gases released from the sewage but theyre not harmful, Haq said. Firefighters and hazardous materials experts had been called to the scene. U.N. management officials were working to deal with the sewage problem, he said. Security officials had earlier told a crowd of reporters and U.N. officials in the street outside the U.N. compound in Manhattan that there was a gas leak. Both the Security Council and the General Assembly had scheduled meetings on Tuesday, which were relocated to a building adjacent to the U.N. secretariat. The U.N. complex is undergoing a $2 billion refurbishment.