MOSCOW, May 24 - Ukraine's desire to diversify its sources of gas is reasonable and Gazprom might have to lower its gas prices for Ukraine, Valery Yazev, head of the Russian Gas Society, said at a press conference.

Commenting on Russia's criticism of reverse gas supplies from the EU to Ukraine, Yazev said: "If Russian-Ukrainian agreements, or Russian-European agreements with Hungary, Romania, Bulgaria are not being broken, then how can we criticize?"