Russia has rejected U.S. warnings against signing an oil-for-goods contract with Iran.
Deputy Foreign Minister Sergei Ryabkov said Moscow wouldn't be intimidated by threats.
Quoted by the state RIA Novosti news agency on April 9, Ryabkov said that an increase in Russian-Iranian trade was a "natural process that doesn't involve any elements of political or economic challenge to anyone."
Ryabkov said he was unaware of any specific agreements, adding that a "normal exchange of opinions with Iranian colleagues has been going on to determine which sectors of economy are best suited for further development of ties."
The Russian business daily "Kommersant" has reported that Moscow plans to buy 500,000 barrels of Iranian oil a day.
If the deal goes through, analysts say it will violate an export limit spelled out in an interim nuclear agreement world powers and Iran reached last year.
On April 7, U.S. Secretary of State John Kerry said Washington could impose sanctions if Russia and Iran move forward with the oil contract.
Based on reporting by AP