MOSCOW: Russia's upper house of parliament ratified the new US nuclear disarmament treaty Wednesday, the final step in approving the first nuclear pact between the two former Cold War rivals in 20 years. Senators at the Federation Council voted unanimously to approve the new START treaty, which US President Barack Obama and his Russian counterpart Dmitry Medvedev signed in Prague on April 8, 2010. The new Strategic Arms Reductions Treaty (START) reduces old warhead ceilings by 30 percent and limits each side to 700 deployed long-range missiles and heavy bombers. Russia's State Duma lower house of parliament backed the measure in the third and final reading on Tuesday and the US Senate ratified the pact after a months-long debate on December 22. NATO Secretary General Anders Fogh Rasmussen hailed the vote as “good news for international security and stability.” His message was backed by Mikhail Margelov, the Federation Council's international affairs committee chief who was one of the pact's principal backers in Russia. “The START agreement verifies the trust between the two sides,” he said after the vote. The original 1991 START agreement expired at the end of 2009 amid differences in readings of what constituted 21st century threats. Those differences also remained throughout the tortuous negotiating and approval process, with both the Senate and Russia's parliament adopting a series of non-binding amendments that put their own spin on the new pact. One of the most fundamental disagreements concerns a US decision to pursue a European missile defence shield that Russia had spent years resisting. Moscow has since modified its stance, saying that it was ready to see the shield go up, but only if it was giving an equal say in how it operates and in determining which nations posed a real threat to the West. Obama and NATO have responded with extreme caution, noting that a joint system would require an unprecedented level of data and intelligence sharing and overcoming various technological stumbling blocks. Moscow and Washington held a new round of missile defense talks last week, but those meetings ended with Medvedev reaffirming that Russia would be forced to deploy more nuclear weapons if it was left out of the shield. Defense Minister Anatoly Serdyukov expanded on that message on Wednesday, telling Russia's senators that the country would be forced to deploy its own missile systems if its stance was ignored by the West. “As far as our own ballistic missile defenses are concerned, we are continuing to develop them just as we had done in the past,” Serdyukov said. Although there has been little compromise on missile defenses since NATO and Russia held a historic summit in November, both sides appear ready to engage in more talks. Rasmussen said he hoped that START's ratification “will help Allies and Russia to make concrete progress in their strategic partnership, including in the field of missile defense.” On Wednesday, the director of a Moscow institute that makes the new long-range Bulava missile said Russia was preparing to dramatically boost production in the coming years.