The financial blockade on Russia, which some call the most extensive sanction regimen in modern history, has eroded its economy and undermined post-Soviet modernization efforts. Extensive sanctions have similarly cut off Iran from key markets, damaging its economy and its currency, which in recent months has fallen about 30% to a historic low.

Linking their financial systems will allow Tehran and Moscow to coordinate sanctions avoidance and take advantage of holes in national sanctions regimes that affect each differently. While Russia’s central bank declined to comment on the deal, as many as 700 Russian banks and 106 non-Russian banks from 13 different countries will be connected to the system.