"The US is not in a position to accuse other countries of supporting terrorism," Spokesman of Iran's mission at the UN in New York Alireza Mir-Yousefi said, reacting to the US state department's 2012 annual report on terrorism.
He further reiterated that the US support for terrorist groups in the region, Israel's state-sponsored terrorism and the terrorist Mojahedin-e Khalq Organization (MKO, also known as the MEK, PMOI and NCRI) shows Washington's double standards in confronting the phenomenon of terrorism.
Mir-Yousefi underlined that the Islamic Republic of Iran which is a victim of state-sponsored terrorism has fought terrorist groups through different possible means for decades.
The US recently allowed the MKO to open its Washington office just a block away from the White House.
The opening of the office of the National Council of Resistance of Iran (NCRI), an umbrella group dominated by the MKO, was attended by several former US officials.
The US permission to the MKO to open its branch in Washington came as American officials have said that they "don't consider the MKO a viable Iranian opposition group or believe it can promote democratic values in Iran", Radio Free Europe said in a report.
Yet at the April 11 inauguration of the office, President Barack Obama's former national security adviser, US General James Jones said the opening of the office was an "important moment" and "a step in the right direction."
Former US Ambassador to the United Nations John Bolton, former US Assistant Secretary of State for Public Affairs P.J. Crowley, former US Representative Patrick Kennedy, and the former deputy director of the CIA's National Clandestine Service, John Sano, were also in attendance.
In the past, former US officials have reportedly been paid large sums of money to speak at the MKO's public events and lobby the State Department on its behalf.
The US formally removed the MKO from its list of terror organizations in early September, one week after the then Secretary of State, Hillary Clinton, sent the US Congress a classified communication about the move. The decision made by Clinton enabled the group to have its assets under US jurisdiction unfrozen and do business with American entities, the State Department said in a statement at the time.
An aide to former US Secretary of State Colin Powell expressed deep regret over the removal of the terrorist group from the US blacklist, stressing that MKO is still a terrorist group.
"I think delisting the MKO was a terrible move in all aspects," Colin Powell's Chief of Staff Colonel Lawrence Wilkerson said in an interview with Real News Network in November, 2012.
"A terrible move because it basically acknowledged a terrorist group is now not a terrorist group anymore, and they clearly certainly still are," he added.
The MKO, founded in the 1960s, blended elements of Islamism and Stalinism and participated in the overthrow of the US-backed Shah of Iran in 1979. Ahead of the revolution, the MKO conducted attacks and assassinations against both Iranian and Western targets.
The group started assassination of the citizens and officials after the revolution in a bid to take control of the newly-established Islamic Republic. It killed several of Iran's new leaders in the early years after the revolution, including the then President, Mohammad Ali Rajayee, Prime Minister, Mohammad Javad Bahonar and the Judiciary Chief, Mohammad Hossein Beheshti who were killed in bomb attacks by MKO members in 1981.
The group fled to Iraq in 1986, where it was protected by Saddam Hussein and where it helped the Iraqi dictator suppress Shiite and Kurd uprisings in the country.
The terrorist group joined Saddam's army during the Iraqi imposed war on Iran (1980-1988) and helped Saddam and killed thousands of Iranian civilians and soldiers during the US-backed Iraqi imposed war on Iran.
Since the 2003 US invasion of Iraq, the group, which now adheres to a pro-free-market philosophy, has been strongly backed by neo-conservatives in the United States, who argued for the MKO to be taken off the US terror list.
In September 2012, the last groups of the MKO terrorists left Camp Ashraf, their main training center in Iraq's Diyala province. They have been transferred to Camp Liberty transient facility near Baghdad.