Ukraine may stop all natural gas imports from Russia within the next few years if the current gas contract is not reviewed, Prime Minister Mykola Azarov said Thursday. "Under the existing gas prices we have reduced and will continue to reduce [gas imports], and in the future – and this is not an empty threat – Ukraine may stop buying gas altogether at that price," he said in an interview with RIA Novosti and Rossia-24 TV channel. "In the next ten years – that is even too long," he added. Ukraine will end its dependence on Russian gas imports by enhancing energy efficiency, reducing gas consumption, using alternative sources of energy and increasing its own gas production, Azarov said. Kiev and Moscow have a long history of disputes over natural gas deliveries, in particular over pricing, and have been arguing over the terms of a 2009 gas contract for the past few years. In one of the most recent disputes, Russian gas giant Gazprom presented Ukrainian state energy company Naftogaz Ukrainy with a $7 billion bill in January, saying the country should pay for gas it did not use in 2012. Under the 2009 contract, which cannot be adjusted to fluctuations in demand, Ukraine must pay for at least 33.3 billion cubic meters of gas per year on a "take or pay" basis.