In the period of 1999-2007 he was Ambassador Extraordinary and Plenipotentiary, representative for Romania at the International Organization in Vienna, in this position he chaired the Permanent Council of the Organization for Security and Cooperation in Europe (COSCE) in 2001; President of the Reform Group COSCE (2004); President of the Group which elaborated the action plan for the improvement of the situation of Roma-Sinti population in the COSCE region (2003); President of the Preparatory Commission of the Organization of the Pact for the banning of nuclear experiments- PCOPBNE (2002); President of the francophone states group in Vienna. During the period 1971-1999, he served in the United Nations: he was a special representative of the General Secretariat of UN for Georgia and Head of UN Mission Observers in Georgia- COMOG (1995-1999), Head of the UN Mission of Observers in Tajikistan – UNMOT (1993-1995), Senior Adviser of the Deputy Secretary General for Human Rights (1998-1992). He was the first Director of the UN Institute for Disarmament Research (UNIDR) in Geneva (1980-1987); he was superior political adviser for the UN Center for Disarmament in New York (1973-1080). Starting in December 1985 until February 1988 he prevented from exercising his functions within the UN, being detained in Romania under political circumstances by the communist regime. He was a member of the Permanent Mission of Romania to the UN in New York (1963-1967). In 2015 National School of Political Science and Public Administration granted him the title of Doctor Honoris Causa. Awarded the Order of Diplomatic Merit in the rank of Grand Officer (2007), Faithful Service National Order in the rank of Grand Officer (2000), DUSTI National Order of the Republic of Tajikistan (2005), League of Honor of National Order of the Republic Of France in the rank of Officer (2009) and also the OSCE Medal: “Bene Merenti ad OSCE” (2002). Author of works focused on subjects as disarmament and international security, extra-atmospheric space, public international law, human rights, international operations for maintaining peace. He has finished the International Relations Institute in Moscow- IRIM.