Moscow, Jan 28 : The Russian parliament on Wednesday ratified President Vladimir Putin's bill on a five-year extension of the New Strategic Arms Reduction Treaty (New START). At a plenary session on Wednesday, the State Duma, or the lower house of parliament, approved the bill submitted by Putin on Tuesday on the extension of the significant arms control pact between Russia and the US, the Xinhua news agency reported. The New START reached by the world's two largest nuclear powers cannot be "overestimated" and it is of great significance for the whole world, said State Duma Chairman Vyacheslav Volodin. Shortly after that, the Federation Council, or the upper house of parliament, also greenlighted the bill. "The New START is being extended for five years without any additional conditions. This is our stance and this is our success!" said Konstantin Kosachev, chairman of the Foreign Affairs Committee of the Federation Council. Russia and the US have started expert-level work on the extension of the New START, Russian Foreign Ministry spokesperson Maria Zakharova said on Monday. Also on Monday, Russian Security Council Secretary Nikolai Patrushev and US National Security Advisor Jake Sullivan held a phone conversation to discuss the extension of the New START and Russian-US cooperation in the field of security. In 2010, Washington and Moscow signed the New START, which stipulates limits to the numbers of deployed nuclear warheads and strategic delivery systems by both. The key pact, the last remaining nuclear arms control treaty in force between the two nuclear superpowers, will expire on February 5. /IANS