MOSCOW, June 25 (RIA Novosti) - Russia's Federal Anti-Monopoly Service has not ruled out that charges of price collusion could be brought against Russia's major aviation fuel suppliers as part of an investigation into price hikes in aviation fuel, the anti-monopoly body said in a statement on Wednesday.

Russian aviation fuel prices have doubled this year, surpassing the average global level. According to the state anti-monopoly service, aviation fuel prices remained almost unchanged from January 2006 to November 2007, but have seen a 70% increase from November 2007-June 2008.

According to the anti-monopoly service, one of the reasons why prices for aviation fuel are higher than in airports abroad is the huge difference between the cost of fuel at oil refineries and prices for plane fuelling.

The anti-monopoly service says the difference may be a result of resale surcharges.

Wholesale prices of aviation fuel sold abroad directly by oil refineries are reportedly significantly lower than those for fuel sold on the domestic market.

A number of charges have already been brought against fuel sellers in regional airports in Russia's Far East and Siberia.