The US has threatened to suspend the opening of a key pipeline to send Russian gas to Western Europe, if Russia invades Ukraine.
Nord Stream 2 will travel from Russia to Germany, and on Thursday officials in Berlin said the operation could face sanctions if Russia attacked.
Western allies say they will target Russia’s economy if it attacks, and recent comments show the strength of their stance on a profitable pipeline.
Russia denies plans to attack.
But the construction of tens of thousands of Russian troops on the Ukrainian border in recent weeks has created tensions and increased fears of attacks.
“I want to be clear: if Russia invades Ukraine in some way, Nord Stream 2 will not move forward,” US Secretary of State Ned Price told NPR.
But he added “he will not go into details” of how it will be suspended, and there are still questions about whether the US will be able to cancel the project.
“We will work with Germany to ensure that it does not move forward,” Mr Price said.
Although the US has insisted it will suspend the pipeline completely, Germany has stated it will not lift sanctions on the project.
The country’s foreign minister, Annalena Baerbock, has told parliament that her Western allies are “working hard for sanctions” that include features “including Nord Stream 2”.
But he added that he would like to “continue the dialogue” with Moscow.
Her comments come after German ambassador to the US Emily Haber wrote on Twitter that “nothing will come off the table, including Nord Stream 2” if Russia violates the “Ukrainian sovereignty”.
The 1,225km (760-mile) pipeline took five years to build and cost $ 11bn (£ 8bn). The power project, which will start under the Baltic Sea, is designed to double the Russian gas exports to Germany.
But so far it has not started to work, as regulators say in November it does not comply with German law and suspended its authorization.
Big European companies have invested heavily in Nord Stream 2, owned by former Chancellor Gerhard Schröder. But many groups oppose the plan.
Environmentalists question how it would fit into Germany’s efforts to reduce pollution and tackle climate change, while politicians at home and abroad fear that it could boost Europe’s confidence in Russia’s power.
Ukrainian President Volodymyr Zelensky has described the pipeline as a “dangerous geopolitical weapon”
Significant change of tone
For years, the official line of the German government regarding Nord Stream 2 was to pipeline a private non-political business project.
Despite intense American pressure, including threats from sanctions against European companies involved in the operation, Berlin refused to back down. Some have accused Washington of interfering with Germany’s independent energy policy.
That changed last week, when German Chancellor Olaf Scholz was asked if Nord Stream 2 would be used to respond to Russian violence. “Everything will be discussed if there is a military intervention against Ukraine,” he said.
That may not sound like hawks, but considering the huge cost of canceling a project it can be considered a major threat.
This pipeline is controversial in Germany. The Green Party in particular has always been opposed to it, for natural reasons. But the SPD chancellor left center center traditionally supports the pipeline, believing it is crucial to the use of German power.
The construction of Russian troops on the Ukrainian border has achieved what years of American oppression has never happened: it has made Germany rethink Nord Stream 2. line
Diplomatic measures
The threats with Nord Stream 2 follow the official day of governance on Wednesday.
The US rejected Russia’s significant request to prevent Ukraine from joining the Nato alliance, while providing what it called a “critical cooperation” approach to Moscow.
President Vladimir Putin is currently examining the proposals, his spokesman said.
The proposals will not be made public, but US Secretary of State Antony Blinken said the document made clear “their core values”, including the Ukrainian sovereignty and its right to choose to join the security forces such as Nato.
Russian Foreign Minister Sergei Lavrov said the official response did not address Russia’s “main concerns” about the expansion of the coalition. But he said it “offers hope for the beginning of a critical conversation” in the second question, adding that President Putin will decide how to respond.
Separately, strategists from Russia, Ukraine, France and Germany reaffirmed their commitment to a ceasefire in Ukraine, which saw Russia-backed rebels occupy the eastern Donbas.
All four countries continue to support the suspension of arms “despite other disputes” over the 2015 Minsk agreement, “a statement issued by the French president’s office said. The group is expected to meet again in two weeks in Berlin.
On Thursday, President Joe Biden spoke to the president of Ukraine by telephone. “[We have discussed] the recent communications efforts to reduce the level and … [I] thank President Biden for his continued military assistance,” Mr Zelensky said shortly afterwards.
President Biden will meet again with German Chancellor Olaf Scholz on February 7 to discuss the situation in Ukraine, the White House said.