 Ukraine also agreed to lease major parts of its new bases in Sevastopol to the Russian Black Sea Fleet until 2017.During the presidency of Victor Yushchenko the Ukrainian government declared that the lease will not be extended and that the fleet will have to leave Sevastopol by 2017.Amid several Russia–Ukraine gas disputes, including a halt of natural gas supplies to European countries, the price that Ukraine had to pay for Russian natural gas was raised in 2006 and in 2009.