Foreign Ministry spokesman Ramin Mehmanparast said the US was the biggest supporter of terrorism in the world in the past three decades.
He said the US tried to cover up its own terrorist nature by putting up claims against other countries and accusing them, ILNA reported.
Based on a report by Iran's Foreign Ministry Website on Thursday, the spokesman further termed as baseless and condemned the accusations about Iran's alleged role in world terrorism raised in the US State Department Annual Report.
He stressed the need for stopping the present trend of raising baseless and biased claims against countries as agents and backers of terrorist operations and warned that the trend could have unfavorable impacts on the international trust and mutual confidence which is a basic element in the world stability and security.
Mehmanparast noted that while the Islamic Republic of Iran attached special importance to its cooperation with the international community in anti-terrorism campaign, the Western countries and the US in particular followed a double-standard policy towards the issue.
He said examples of such a policy was the extensive activities of the members of the terrorist Mojahedeen Khalq Organization (MKO) in these countries and their close relationship with the political figures there.
He also pointed to the role of some of Western countries and their intelligence services especially those belonging to the US in supporting the terrorist organizations working against Iran like the grouplet led by Rigi and the PJAK as other cases of such a behavior.
He further pointed to the remarkable increase in the opium production which provides the financial resources for terrorism and extremism as the result of the presence of the US and Western military forces in Afghanistan.
The Iranian Foreign Ministry spokesman went on to point to the support of the US for the terrorist acts of the Zionist regime in massacring the defenseless Palestinian and Lebanese peoples as other examples of the US administration's role in expanding terrorism.
Mehmanparst concluded by noting that the international community had been suffering much of the unilateralist views of the US, stressing that Washington has to be pressured to change its attitudes.