The head of the UN watchdog agency on Friday accused UN staff of mounting a smear campaign against him as he faced a renewed probe of allegations he traded jobs for personal favours. Dileep Nair, head of the UN Office of Internal Oversight Services, whose contract expires on April 23, launched a counter-attack after being told he was subject to a second review on improper job promotions and "sexual contact." Nair and his attorney released documents from UN Secretary-General Kofi Annan and others that showed he was cleared of the allegations in November stemming from an employees union, the UN Staff Council. His argument with the United Nations follows a drumbeat of recent glum news for the world body, with both managers and staff more emboldened to go public following probes into the scandal-tainted oil-for-food programme in Iraq.