The Russian-led Eurasian Economic Union has signed a free trade agreement with Iran.

The deal was signed on the sidelines of the Supreme Eurasian Economic Council in St. Petersburg on Monday. The union comprises five countries that were part of the former Soviet Union.

Russian President Vladimir Putin hopes to expand economic cooperation with Iran. He said the agreement is extremely significant as Russia seeks to strengthen ties with Iran.

Putin invited Iranian President Ebrahim Raisi to Moscow earlier this month, amid mounting Western economic sanctions on both Russia and Iran.

Armenian Prime Minister Nikol Pashinyan also attended the meeting, despite speculation that Armenia was distancing itself from Russia.

Pashinyan skipped recent Russian-led summit meetings. His move was seen as a sign of his frustration with Russia over the conflict between Armenia and Azerbaijan. Azerbaijan's military offensive in the disputed Nagorno-Karabakh region in September forced local ethnic Armenians to virtually surrender.

Putin is expected to hold an informal meetings of leaders of the Commonwealth of Independent States in St. Petersburg on Tuesday in an apparent bid to shore up unity among the countries, including Armenia.