MOSCOW, Sept 22 (Reuters) - Trade on the spot market is behind the surge in natural gas prices in Europe, a Kremlin spokesman said on Wednesday, reiterating that Russian state energy giant Gazprom is sticking to its contractual obligations in full.

The spokesman, Dmitry Peskov, also said that Russian gas supplies to Europe through Ukraine after 2024, when the current transit deal expires, depend on gas demand. (Reporting by Gleb Stolyarov; writing by Vladimir Soldatkin; Editing by Louise Heavens)