Mottaki, who arrived in Baghdad from Syria Wednesday on an official visit and met with Iraqi Foreign Minister Hosyar Zebari, was reported by the official Iranian news agency IRNA to be holding talks with participating countries prior to the Iraqi conference in Istanbul, Turkey.
Iran believes the U.S. led-coalition force is causing instability and continuing violence in Iraq, and Tehran is calling for the urgent withdrawal of military forces and the complete transfer of authority to the legitimate Iraqi government.
Mottaki denied U.S. allegations that Iran was behind the deaths of American soldiers in Iraq saying, the "U.S. administration is lying to the American nation."
The move was echoed by the Iranian spiritual leader and head of state Ayatollah Ali Khamenei: "The idiotic policies of the United States in Iraq have led to the killing of its troops," the AFP news agency quoted him as saying on state TV.
Washington introduced harsh penalties against Iran's military and state-owned banks last week, qualifying its Revolutionary Guard Corps as a proliferator of weapons of mass destruction and its elite Qods Force a supporter of terrorism.