Nor should Europe discourage the creation of large energy groups, he said when asked to comment on recent moves toward concentration in the European energy sector.

Energy independence "is totally inaccessible, as much for Europe and for the United States and Japan", Mandil said in an interview published Tuesday in the French business daily Les Echos.

The key, he said, lay in "the flexibility of supplies", including gas from Russia, cautioning that developed economies should "not put all their eggs in one basket".

Europe's access to energy from Russia -- far from being a "catastrophe," as described by some after shortfalls in delivery provoked by Russia's standoff with Ukraine in January -- is "an exceptional opportunity", Mandil asserted.

It was also clearly in Russia's interest to open its gas sector, he added, saying that the G8 meeting slated for July in Saint Petersburg would be a excellent opportunity to convince Moscow.

"It is in their interest to open up the game because, despite high prices, Gazprom" -- which holds a state monopoly on gas exports -- "does not have sufficient means to invest in production", Mandil said.

Also on Tuesday, Russian President Vladimir Putin said that Russia was considering constructing a gas pipeline that will link it to the Chinese market.

"We envisage the possibility of constructing a gas pipeline system across the Russia-China border," Putin told Russian reporters.

The IEA chief, referring to controversy over a French plan to merge Gaz de France and Suez, said that he was not "among those who are worried about the idea of seeing large groups emerge" in Europe's energy sector.

"Neither a Suez-Gaz de France merger nor a Suez-Enel grouping bother me, as long as competition can develop without hindrance," Mandil said. "In other words, as long as each consumer can truly make choices about his supplier."

Madil's comments come against a backdrop of intense maneueving in Europe's energy sector.

Rome has accused France of seeking to keep Italian energy group Enel from bidding for French utilities group Suez by charging state-controlled Gaz de France to make a pre-emptive offer for the French company.