There is no need to subject the gas agreements between Russia and Ukraine to outside checks, Russia\'s Foreign Ministry said on Thursday, a day after Ukrainian Energy Minister Yury Boyko said that Kiev had prepared all the documents needed to seek a revision of the contracts in Stockholm arbitration. \"Any attempts to challenge the above-mentioned Russian-Ukrainian agreements are unjustified from a legal point of view. The absolutely clear legal framework of the issue does not require any external audit and should be adopted by everybody who is interested in ensuring Europe\'s energy security,\" the ministry said in a statement. Tensions between the two Slavic states often flare in the middle of the winter, as Moscow and Kiev struggle to agree the price of gas. The spats sometimes result in Ukraine shutting off export pipelines to Europe. The last time, in 2009, the row ended in the signing of a 10-year agreement, which Ukraine has been trying to revise since 2010, when President Viktor Yanukovich came to power. The deal ties the price of gas to the price of oil, which has been rising steadily, boosting Kiev