Gary Lewis said in interview with IRNA that Iran is acting as a source of peace and stability in the region.
He noted that other countries need Iran's assistance in fighting terrorism and extremism as well as settling regional disputes.
Lewis is a UN veteran whohas been working for the UN in Asia, Africa, Europe, the US and the Middle East for more than 25 years.
When questioned about UN programs to confront the seemingly increasing power of terrorist groups within the past decade, he expressed sympathy with the victims of terrorism and condemned all forms the phenomenon.
He further urged all world countries to fight terrorist groups' activities by targeting the ideological roots of their thinking, underlining that his organization has always slammed terrorist acts.
He noted that the UN adopted a global anti-terrorism strategy in 2006 as an action plan urging member states to initiate campaign against terrorism at regional and international levels.
Lewis expressed regret that world countries held divergent views on terrorism leading to lack of an agreement on ways of dealing with terrorist operations.
But, he noted, the UN was trying to activate all national and international potentials by requiring world countries to condemn terrorism in all forms.
On Iran's role in settling regional disputes, the UN official said that Tehran has been playing outstanding role in the ME region, stressing that the international community should always consider Iran as a part of regional strategy.