Europe could be heading for a new energy crisis as Russia and Ukraine trade blows in an escalating price war that threatens to trigger a re-run of January's cuts in Russian gas exports to the continent.
As rich nations prepare for talks on energy security next month in St Petersburg, Europe is on edge as the long-running dispute between Ukraine and the continent's biggest gas supplier Russia flares again.
In January a similar stand-off left some of Europe's biggest economies running close to empty during unusually cold weather.
This time threats by Turkmenistan, one of Russia's own suppliers to turn off the taps unless it gets higher prices, has fanned further concern.
Russia's assertions last week that Ukraine was stealing gas and failing to refill storage tanks quickly enough set alarms bells across Europe, which takes a quarter of its gas from Russia.
"It seems like all the makings of a perfect storm," said Jeffrey Woodruff, a director of the energy group at ratings agency Fitch.
"Any of the events in isolation could be enough to spark new supply interruptions in Europe, but all of them colluding near the beginning of the G8 summit on energy security seems unbelievable."
January's drop in Russian supplies to Europe came after Moscow halted supplies to Ukraine, which rejected steep price increases designed to move contracts into line with world market levels. About 80 per cent of Russian supplies are pumped west via Ukraine.
Russia said Ukraine siphoned off gas destined for Europe, leaving big consumers like Germany, France and Italy facing shortages and needing to tap emergency stocks.
Yulia Tymoshenko, poised to be reinstated as Ukraine's Prime Minister, last week said she wanted to review price terms that were finally agreed in January, re-igniting the row with Moscow.
Russia's gas monopoly Gazprom, which wants to raise prices further, made fresh allegations that Ukraine was stealing gas, and said Ms Tymoshenko's stance could trigger a new gas crisis in Europe.
"We don't have anything in sight which looks like an agreement," Jonathan Stern, gas specialist at the Oxford Institute for Energy Studies, said.
"Ukraine is a huge problem, it is not nearing resolution and nobody knows what to do about it," Mr Stern added. Mr Stern said Ms Turkmenistan's demand for Russia to pay more for gas meant Moscow could try to pass on this potentially increased cost to Ukraine, strengthening its resolve to increase Ukraine's bill.
The only silver lining is that this time the dispute has come to a head during summer, when gas demand is lower than in winter. Otherwise, Europe is no better prepared to cope than it was in January, analysts said.
Calls for more storage capacity and diverse gas supplies in the wake of January's crisis have made little impression so far, although firms are lining up more projects to import liquefied natural gas (LNG) from a variety of sources around the world.
"There's no more additional supply flexibility," Nick White, head of energy at Arthur D. Little in London, said. Traders said high prices in Britain for next winter partly reflect the risk of interruptions to Russian supplies.
Britain, Europe's biggest and most liquid gas market, is less reliant on direct supplies from Russia than its continental neighbours. However, its growing reliance on imports from the mainland mean it is vulnerable to potential supply problems in France and Germany.
Despite its outwardly tough stance with Ukraine, Gazprom will be reluctant to risk further damage to its reputation as a solid supplier, analysts said.
"The end game for Gazprom is to be one of the pre-eminent gas players in the world," said Frank Harris at Wood Mackenzie. "To achieve this you have got to have a reputation as a fundamentally reliable supplier."