"If the threat from Iran's nuclear and ballistic missile program is eliminated, the driving force for missile defense in Europe will be eliminated," US President Barack Obama said Tuesday. The US president was speaking to students at the National Economic School (NES) in Moscow, on the second day of a visit to Russia. "In the short period since the end of the Cold War, we have already seen India, Pakistan and North Korea conduct nuclear tests. Without a fundamental change, do any of us truly believe that the next two decades will not bring about the further spread of nuclear weapons? "That is why America is committed to stopping nuclear proliferation, and ultimately seeking a world without nuclear weapons ... And while I know this goal won't be met soon, pursuing it provides the legal and moral foundation to prevent the proliferation and eventual use of nuclear weapons," Obama said. Just the day before, Obama and Russian President Dmitri Medvedev signed a mutual agreement to gradually scale back the number of nuclear warheads held by each country. But in his statement Tuesday, Obama mentioned in a single sentence two contentious issues between the US and Russia: The missile defense system and Iran's nuclear ambitions. Installing a missile defense system in Eastern Europe, in countries that formerly were part of the soviet bloc, was a move initiated by Obama's predecessor George W. Bush but heavily contested by Russia. On Iran, the US has long sought the full cooperation of both Russia and China, two major players whose economic concerns have so far prevented concerted, international sanctions against Iran, aimed at forcing the Islamic republic to abandon its nuclear program.