American officials have said the missile defenses it wants to install in Europe will protect NATO allies and counter any threat from Iran. Russia has long opposed the plan, and sees the system as a threat to the viability of Russia's own nuclear arsenal as a deterrent.
In Geneva last month, leading world powers reached a deal with Iran to ensure that its nuclear program remains peaceful. Russian Foreign Minister Sergey Lavrov told reporters after a meeting today with NATO counterparts there's "no reason" for the missile defense plan if that deal is implemented fully.