Currently Greece imports gas from Gazprom at a price of between $4.6 and 4.7 /mn Btu, Kitsakos said; from Turkey's Botas at $5.9/mn Btu; and from Algeria's Sonatrach at $6.5/mn Btu. Gas at the Dutch TTF is around $6/mn Btu. However, the price Cheniere will ask for gas is rumoured to be around $7/mn Btu.

The 180-km (110-mile) pipeline will be built by a Bulgarian-Greek joint venture that also includes Italian energy group Edison SpA.

After the cancellation of the South Stream natural gas pipeline last December due to the EU’s blockage of the project, Russia announced an alternative project called the Turkish Stream which will hit the shore on the European side of Turkey near Kıyıköy.

Oil prices suffered their biggest selloff in five months on Monday, falling as much as 8 percent as Greece's rejection of debt bailout terms and China's stock market woes set off a deepening spiral of losses.

Greece moving down oil prices. Oil prices fell on Monday, with U.S. crude dipping below $59 per barrel to an almost three-week low, after Greece imposed capital controls as lenders refused to extend the country's bailout.

If Greece withdraws from the Turkish Stream project, which is planned to transfer Russian natural gas to Europe via the Turkish-Greek border, the U.S. will expect the International Monetary Fund (IMF) to reward Greece

Greece expected to sign a memorandum on Turkish Stream during the St. Petersburg International Economic Forum, which will be held June 18-20.

Greece's energy minister has discussed in Moscow the construction of a pipeline that will transport Russian gas to Europe through its territory, the Greek energy ministry said on Saturday.

Athens expects to agree to take part in a pipeline that would bring Russian gas to Europe via its territory, Greece's energy minister said on Friday, estimating the project would cost 2 billion euros ($2.1 billion).

Relations between Greece and Russia appear to be strengthening after Tsipras confirmed his opposition to Western sanctions on Russia. He claimed that the Greek government helped block European proposals to increase the scope of the sanctions.