Iran on Saturday slammed the United States for removing an exiled Iranian opposition group from its blacklist of designated terror groups, accusing Washington of "double standards" in dealing with terrorism, according to state media.
The delisting of the People's Mujahedeen of Iran, or Mujahedeen-e-Khalq (MEK), was announced on Friday, ending a complex legal battle fought through US and European courts.
The group invested much money and years of intense lobbying to be taken off the list.
The move paved the way for the MEK, whose leadership is based in Paris, to legally access any assets it has in the United States and to conduct business with Americans freely.
Iran's foreign ministry, in a statement reported by the ISNA news agency, said the move proved the US government "applies double standards when it comes to terrorism."
"Iran strongly condemns the irresponsible action of the US government... which is now responsible and should answer for all of the terror acts the (MEK) has done and will do in the past, present and future," it said.
The leftwing group was founded in the 1960s to oppose the shah of Iran. After the 1979 Islamic revolution that ousted the shah it took up arms against Iran's clerical rulers.
The MEK says it has now laid down its arms and is working to overthrow the Islamic regime in Tehran through peaceful means.
But Iran is holding the group responsible for murdering thousands of Iranian civilians and officials as well as becoming mercenaries for the former Iraqi regime of Saddam Hussein, the foreign ministry said.
With the removal of the MEK off the terrorist list, the ministry added, "the US government proved that none of its actions correspond to logic ... as it is now officially and practically supporting all of the MEK's crimes and terror acts against Iranian, Iraqi and even US citizens."