Russia’s decision to lift a self-imposed ban on supplying an advanced air defense system to Iran is reverberating in Washington, where officials worry the move could lead to a series of complications, some of which could further destabilize the Middle East.

Some of the harshest criticism came from the State Department, which said Secretary of State John Kerry had voiced Washington’s concerns directly to Russian Foreign Minister Sergei Lavrov.

Earlier Monday, the Kremlin"s website reported Putin had signed a decree lifting a ban on providing Iran with the S-300 system. The announcement Monday comes as world powers are trying to negotiate a final nuclear deal with Iran, aimed at curtailing Tehran’s nuclear program to ensure it does not develop nuclear weapons.