Staff returned to the UN building in the South African capital Pretoria today after a search of the offices following a bomb scare, a senior UN official said.
"We are on heightened security alert since the attacks in New York and Washington", said Mr John Ohiorhenuan, the UN Resident Coordinator in South Africa.
"This morning the police dogs showed signs of uneasiness and police advised us to evacuate the building so a search could be carried out. Nothing was found and we are now back to normal business", he added.
South Africa has been on high alert since last week's suicide attacks. The US and British embassies have been placed under heavy security protection.