Russia's foreign minister is warning the United States against trying to impose unilateral sanctions against Iran.
Sergei Lavrov said Thursday that the U.S. does not seem to understand that countries facing sanctions from the United Nations Security Council should not face additional, unilateral sanctions "under any circumstances."
Despite the differences, Lavrov said Russia's relationship with the U.S. is improving.
The U.S., Russia and other Security Council members have been discussing a fourth round of sanctions against Iran for its nuclear activities.
Earlier this week, European Union foreign policy chief Catherine Ashton said the Security Council resolution could be ready in the next month and a half.
The U.S. and its allies accuse Tehran of pursuing nuclear weapons, although Iran insists its program is for peaceful purposes.
On Wednesday, Iranian President Mahmoud Ahmadinejad called U.N. Security Council resolutions "worthless" and said Tehran will not back down from pursuing its nuclear program.
Speaking Wednesday to a crowd in the southern Iranian city of Yasuj, Mr. Ahmadinejad dismissed U.S. efforts to impose new sanctions on Iran and said U.N. resolutions are "not worth a penny."
Some information for this report was provided by AP, AFP and Reuters.