US President Joe Biden promised there would be no advancement of the Nord Stream 2 gas pipeline project, should Moscow launch an invasion of Ukraine.
Biden was speaking after talks with German Chancellor Olaf Scholz over the tense situation on Ukraine's border with Russia, close to which some 100,000 Russian troops have been deployed.
A key bone of contention between Washington and Berlin has been the construction of the pipeline that is set to pump Russian natural gas directly to Germany, bypassing Ukraine.
Responding to a question on Nord Stream 2, Biden said there would be no chance of the project going ahead if Russian tanks and troops crossed the Ukraine border.
"There will no longer be a Nord Stream 2. We will bring an end to it. I promise you we'll be able to do that."
What did Scholz say?
Scholz — on his inaugural visit to the White House as Germany's chancellor — said "far-reaching measures" had been agreed upon with allies and partners including the US. " We will take all necessary steps. You can be sure there won't be any measures on which we have a differing approach. We will act together jointly."
When pressed on Nord Stream 2, Scholz avoided mentioning the project explicitly but repeated his message of solidarity.
The US State Department previously said it will work with Germany to make sure Nord Stream 2 does not happen in the event of an invasion.
Biden had earlier praised close ties between Washington and Berlin, adding they were "working in lockstep" to further deter Russian aggression.
Scholz has been to the White House before, serving as finance minister and deputy chancellor under his predecessor Angela Merkel, but he has been criticized for delaying his inaugural US visit as chancellor.
He took office 60 days ago. Both former Chancellor Merkel and her predecessor Gerhard Schröder were quicker to head across the Atlantic.
What issues are there between Berlin and Washington?
While the countries have been staunch allies since the end of World War II, Germany is finding itself being increasingly questioned over its commitment to preventing Russian aggression.
Germany has come under criticism over its heavy reliance on Russian energy supplies and its refusal to export lethal weapons to Ukraine.
Russia and Eastern Europe expert at the German Council on Foreign Relations Stefan Meister told DW on Monday that he thought Germany might relent on the pipeline.
"I think Germany will support in the end, economic sanctions also sanctions on Nord Stream 2," he said.
But, on the other big issue — Germany's refusal to sell weapons to Ukraine— Meister thinks "they will not agree. Definitely not. I think Scholz made it again clear that Germany will not send weapons."
Diplomatic efforts to calm the Ukraine crisis
Scholz's trip comes on a day of busy diplomacy on the Ukraine crisis. German Foreign Minister Annalena Baerbock is in Kyiv and French President Emmanuel Macron is visiting Moscow.
Scholz will also return to Berlin on Tuesday for talks with Macron and Polish President Andrzej Duda, it was announced on Monday.
The German chancellor has invited the other two European leaders to "discuss in particular the situation in and around Ukraine," government spokesperson Christiane Hoffman said.
The three partners have maintained a special relationship known as the "Weimar triangle" for 30 years.
"I think it's also about showing that finally, Germany and the European Union are more active on this conflict," Russia expert Meister told DW. "So it's not only up to the US, but it's about European security. And to also show unity with smaller countries, especially in Central and Eastern Europe."
