BRUSSELS (AFP) ― The United States stepped up its war of words over Russian gas on Wednesday, while warning its European allies not to count on American gas supplies in the short-term.

Speaking ahead of an energy meeting between the United States and the European Union in Brussels, U.S. Secretary of State John Kerry said that no country should use energy supply as a “political weapon or an instrument for aggression.” 

No nation should use energy to stymie a people’s aspirations,” Kerry said, adding the United States and the EU were now working “in lockstep” to help Ukraine.

The comments at the U.S.-EU Energy Council talks came a day after Russian-controlled gas supplier Gazprom heaped more pressure on the teetering Ukrainian economy by increasing gas prices by a third, in what EU officials said was “political pricing.”

Ukraine will now pay $385.5 per 1,000 cubic meters of gas from the previous cut rate of $268.5.

In response to the pressure from Moscow, Kerry and his EU counterpart Catherine Ashton revealed plans for a root and branch review of the EU’s dependence on Russian energy supplies and to help Ukraine diversify its gas sources.

The review follows a call by President Barack Obama during a visit to Brussels last week for Europe to reduce its energy dependency on Russia.

Ukraine consumes 50 billion cubic meters of gas a year, of which 20 billion are produced locally and 30 billion are piped in from Russia.

But more importantly, Ukraine’s gas pipelines carry 65 of the 133 billion cubic meters used each year by the EU’s 28 member-states, according to EU data.

Kerry and Ashton said developments in Ukraine had brought energy security concerns “to the fore” and that the United States and EU were now “considering new collaborative efforts to address these challenges.”

One significant change is the expected arrival to the world market of U.S. gas supplies, which have surged with the development of shale gas in North America.

Once export licenses are approved, the United States “will supply more gas (to the global market) than all of Europe consumes today,” Kerry said.

Yet a senior U.S. administration official cautioned that the exports would offer little short-term relief to Russia-dependent European states, including Ukraine.

“It takes time ― we don’t expect the first delivery of natural gas to take place before 2015,” the official said, urging EU countries to take part in an “honest conversation” about energy needs.