KYIV, Nov 22 (Reuters) - Ukraine's gas transmission system operator denied an assertion by Russian gas company Gazprom on Tuesday that Ukraine had withheld 52.52 million cubic meters of gas meant for Moldova, and accused Russia of using gas as a political tool.

"This is a gross manipulation of facts in order to justify the decision to further limit the volume of gas supplies to European countries," it said in a statement. (Reporting by Pavel Polityuk, Editing by Timothy Heritage)