Naftogaz, Ukraine’s largest energy producer, has signed a gas sale and purchase agreement with Germany’s RWE Supply & Trading GmbH, in an attempt to diversify its gas supply routes, the company said on Friday. \"Naftogaz of Ukraine and RWEST have signed a framework agreement about sales and purchases of natural gas. The agreement forms the legal basis for possible natural gas deliveries from RWEST without sales and purchase obligations,\" Naftogaz said in a statement, adding prices and supply volumes will be determined by separate contracts. Ukraine has been seeking to diversify its gas supplies away from Russia following the 2009 gas deal it signed with Russia’s Gazprom. The deal ties the price of gas to oil prices, which have risen strongly since 2009, boosting Ukraine\'s gas bill. Ukraine will have to pay $416 per cubic meter of Russian gas in 2012, and Kiev insists that the price and volume of its gas imports should be reduced. Ukrainian Energy Minister Yuriy Boyko announced this January that the country was seeking to cut Russian gas imports to 27 billion cubic meters, from the 2012 contracted volume of 52 bcm. Russian gas giant Gazprom reacted by saying the current contract did not stipulate unilateral changes in gas purchases.