The US move came following the breakdown of international talks to end the country's nuclear activities.
"The letter makes Ahmadinejad a subject of international talks, particularly in the Middle East."
The dollar fell against other leading currencies as international talk swirled around possible interest rate changes.
He has frequently been involved in international talks, including the Six Party Talks.
The announcement is expected today in Buenos Aires at the 10th round of international talks on climate change.
Neither can we be content in the context of international talks with waiting and wasting time.
It is therefore vital for us to include this subject in international talks.
Certainly, international talks will be required in order to clear up all the details.
In April 2009 North Korea walked out of international talks aimed at ending its nuclear activities.
If this delegation fails, America must lead an international force of armed peacekeepers to contain the violence while international talks continue to find common ground.