Russia's plans to extend its gas link to Germany run counter to EU interests and risk further destabilizing Ukraine, 10 European governments said in a letter to the European Commission that called for a summit-level debate on the issue.
A group of European companies signed an agreement with Gazprom in September to expand its Nord Stream pipeline to Germany, bypassing Ukraine.
On Wednesday, Gazprom said it would halt gas deliveries to Ukraine while Kiev said it could find cheaper supplies elsewhere.
The letter, written on Thursday and signed by Bulgaria, the Czech Republic, Estonia, Greece, Hungary, Latvia, Lithuania, Poland, Romania and Slovakia, says the project should come under the closest regulatory scrutiny and called for "an inclusive debate" at next month's EU summit.
"The position of the European Commission on the Nord Stream II project will also essentially influence the perception of the EU's common foreign and security policy among its core allies and traditional partners," the letter, seen by Reuters, said.
World leaders have been urging Moscow and Ankara to avoid any escalation of tensions following the shooting down of a Russian jet by NATO member Turkey.
Russia's relationships with the European Union and Ukraine have been volatile since the annexation of Crimea in March last year.
The Nord Stream extension to deliver increased volumes of gas straight to Germany could have serious consequences for Kiev and EU nations, the letter said.