The talks will address the findings of a new report by the United Nations nuclear watchdog, the International Atomic Energy Agency (IAEA), released on Friday only to the 35-nation IAEA board and the United Nations Security Council.
"Russian Deputy Foreign Minister Sergei Kislyak will attend the Iran Six meeting in Washington at the level of political directors," the source said.
The five permanent UN Security Council members and Germany agreed at talks in Berlin on January 22 on a draft for a third sanctions resolution against Iran calling for travel bans, asset freezes and vigilance on all banks in the Islamic Republic.
The new draft resolution was officially introduced by France and Britain in the UN Security Council earlier on Friday, and council members are expected to vote on the resolution at some point next week.
The document calls for further sanctions against two Iranian banks, inspections of air freight and shipping companies - Iran Air Cargo and Islamic Republic of Iran Shipping Line - and calls for tighter vigilance by countries trading with or issuing loans to Tehran.
Another change to the original document is a mandatory travel ban on Iranians already subject to sanctions. Previously the resolution called for a discretionary travel ban on entry and transit of individuals.
The draft document also calls for the IAEA and European Union to support the Islamic Republic and to strengthen diplomatic ties with the six nations to resolve the problem surrounding Iran's nuclear program.
The outcome of the vote will largely depend on the assessment of the new IAEA report on Iran's nuclear program.
The diplomatic standoff between Iran and the West began almost six years ago over suspicions that Tehran was developing a secret weapons program. Tehran has always maintained it needs nuclear technology for peaceful purposes. Since then, two rounds of sanctions have been imposed - in December 2006 and March 2007.
