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.

New corridors along the Nord Stream natural gas pipeline through the Baltic Sea to European markets should be in service by 2019, Russia's Gazprom said.

In Budapest, Mr. Šefčovič reported that, in the wake of the cancellation of South Stream last December, all parties in Europe have been paying attention to statements from Russia, as a gas supplier, and Europe's stance on infrastructure has been altered.

Gazprom revived its contract with Italian contractor Saipem (controlled by state-run Eni SpA). The Milan-based company had signed two contracts worth €2.4 bn in total for the construction of an undersea pipeline and support services for construction of a second undersea pipeline, both part of much touted South Stream. The contract terms are now being renegotiated, so as to start construction in time for the 2016 deadline.

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

Slovakian Prime Minister Robert Fico met with Russian Prime Minister Dmitry Medvedev in Moscow and proposed a plan that would transfer gas from the Turkish border through Bulgaria, Romania, Hungary and Slovakia, thereby bypassing Greece.

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.

Russian energy company Gazprom has made it clear that it intends to move forward with the construction of the Turkish Stream natural gas pipeline as quickly as possible, whether or not the project can overcome political obstacles in Europe.

The crisis in Ukraine highlighted the need for Europe to tighten energy links among member states and cut its dependence on Russia, which supplies 27% of the bloc’s natural gas. To ensure that intergovernmental agreements with Russia don’t breach EU law, the regulator should vet their content during negotiations and not just before deals are adopted.

Gazprom has switched to the stage of building the offshore section of the Turkish Stream gas pipeline intended to bring Russian natural gas to Europe via Turkey, Gazprom CEO Alexey Miller said on Friday.