KIEV, Sept. 6 - Ukraine has prepared documents needed to file a lawsuit on the gas dispute with Russia, President Viktor Yanukovych announced, according to the daily Kommersant Ukraina.

Kiev wants Moscow to be guided by the price formula adopted with Germany while defining the price of gas to be shipped to Ukraine, minus transportation costs and the additional discount of $100 per 1,000 cubic meters, laid down in the Kharkiv agreements, Yanukovych said.