ST. PETERSBURG, June 7 (RIA Novosti) - Russia's deputy prime minister and finance minister questioned on Saturday the abilities of oil and natural gas cartels to cut market risks.

"I have a cautious attitude to organizations like OPEC [the Organization of Petroleum Exporting Countries]," Alexei Kudrin said, speaking at an international economic forum in St. Petersburg. "Those institutions cannot reduce market risks, including in terms of prices."

Kudrin cited an opinion shared by OPEC members that oil prices have been 30-35% higher recently due to market speculation.

Prices for crude hiked a further $11 on the New York Mercantile Exchange on Friday to $138.5 per barrel.

Kudrin said he took a similarly cautious approach to plans to create a gas equivalent of OPEC, an idea first launched by then-Russian president Vladimir Putin in 2001 and enthusiastically backed by Iran. Western states have opposed the cartel as a political tool.

A number of major gas producers have established the Gas Exporting Countries Forum (GECF), but have not yet adopted a charter. The forum lacks a strict membership system, but already includes Venezuela, Iran, Libya, the U.A.E. and Russia, and a number of other countries. Norway has observer status.

The member countries currently control about 73% of the world's gas reserves and 42% of its production.