Ashgabat and Moscow have escalated their war of words over Russia's publicly stated doubts about the size of Turkmenistan's natural gas reserves.

The Turkmen foreign ministry issued a sharply worded statement Saturday after Alexander Medvedev, deputy chief executive of the state-owned Russian gas monopoly Gazprom, questioned whether an audit of Turkmenistan's Caspian Sea reserves was accurate.

The countries have been sparring as Turkmenistan President Gurbanguly Berdymukhammedov has moved to lessen his country's dependence on Gazprom as a customer and seeks to open new markets within the European Union and Asia.

Medvedev said in a Russian television interview Friday there "are no grounds" to believe an audit by the British company Gaffney, Cline and Associates that 26.2 trillion cubic meters of gas are held in Turkmenistan's three major gas fields, The Moscow Times reported.

"I believe that there are no grounds … and no reason to make such statements that there is such a natural deposit with reserves of this scale," Medvedev said.

That brought a denunciation from Ashgabat, which says Russia has embarked in a coordinated misinformation campaign to hinder its efforts to more than triple its natural gas output by 2030 through the development of new markets.

"The Foreign Ministry of Turkmenistan notes that such statements by the representative of Gazprom are extremely faulty and disrespectful of partnership relations in the energy sphere," the statement said. "Particular confusing is the fact that such a biased assessment was made public by a professional."

Medvedev's comments were "another clumsy attempt to distort the real situation concerning the natural resources of Turkmenistan, in particular its gas reserves," the statement continued. "This occurs against the background of the increased attacks in the Russian media on Turkmenistan's independent energy policy."

It's not the first time Russia and the former Soviet republic have clashed over estimates of the size of its Caspian Sea gas reserves.

Sergei Pravosudov, director of the Institute for National Energy in Moscow, wrote last month on a Russian Internet news site that the gas in Turkmenistan's Southern Yolotan field is held at a very deep level -- more than 2 miles below the sea bed, Eurasianet.org reported.

Pravosudov cited a report by the British management consulting firm McKinsey and Co. estimating the costs to first extract and then refine the gas to remove sulfur contaminants would make it among the most expensive gas operations in the world.

But Turkmen officials contend costs won't be prohibitive factor, citing $9.7 billion in already-signed contracts to develop the Southern Yolotan field, the Web site said.

The latest flare up came after Deputy Prime Minister Baimurat Hojamuhammedov, who supervises the country's oil and gas sector, and Turkmengaz Chairman Amanali Khanaliyev met with Azerbaijan officials last week at a conference in Baku where the construction of a trans-Caspian pipeline was discussed.

Khanaliyev said the still-unrealized $2 billion pipeline would be capable of supplying 30 billion cubic meters of natural gas annually to Europe while bypassing Russia, the online business news portal ABC.az reported.

"We are negotiating with several international companies that have the necessary experience, technical capabilities and means to raise funds for construction work on individual sections of the pipeline," Khanaliyev said.

Russia and Iran oppose the project, however, saying international boundaries in the Caspian Sea remain unsettled and contending the EU lacks the jurisdiction to support it.