The German-backed Nord Stream pipeline is “a Russian geopolitical project intended to divide Europe and weaken European energy security”, the US secretary of state, Antony Blinken, has warned. The claim on Thursday is likely to send a chill through US-German relations, as the German chancellor, Angela Merkel, has repeatedly claimed the near-complete project – a system of offshore natural gas pipelines – should be seen as an economic rather than political project. Merkel has invested huge political capital in defending the project. With the pipeline so close to completion there had been an expectation that the US would feel the issue was a lost cause, but Blinken said in a statement that firms involved in the project should immediately abandon work or face sanctions. He said the Biden administration was intent on complying with existing bipartisan Congress legislation that calls for sanctions against those working on the project. He said the US was tracking those entities believed to be involved in the project. The Baltic Sea pipeline that bypasses Ukraine – so depriving the country of significant revenues – is 90% complete and could even be operational by June. Blinken’s warning came the day after the US president, Joe Biden, called the Russian president, Vladimir Putin, a killer, a description that prompted the latter to withdraw his ambassador to Washington. Some Republican senators, such as Ted Cruz, have been threatening to disrupt nominations for key administration posts unless the Biden team toughens up its stance on Nord Stream. In its final days the Trump administration had been planning to go as far as sanctioning German entities for their role in the project, former officials said. Those entities included Nord Stream’s German CEO, Matthias Warnig, and the German vessel Krebs Geo. The US has imposed sanctions on the Russian company KVT-RUS, which operates the Fortuna lay ship. There has also been anger in Ukraine that the new administration has not acted more decisively, and even now some in Kiev will note that, despite the tough language, no sanctions have been applied. In a bid to assuage the US, Merkel is due to offer extra economic help to Ukraine this week for the expansion of green hydrogen. “The perception in Ukraine and most of Europe is that US sanctions are intentionally not being implemented in order to allow the Kremlin to finish Nord Stream 2,” said Oleksandr Kharchenko, managing director of Ukraine’s Energy Industry Research Centre. “It’s hard to believe that this is what president Biden wants, but by choosing not to apply US sanctions laws and refusing to sanction the numerous vessels and companies openly engaging in pipe laying, this amounts to a policy of protecting Russia’s Nord Stream 2 pipeline.” German industrialists have been adamant in their support for the pipeline and say US objections reflect American business interests and not any genuine geopolitical fear that Europe could become over-reliant on Russia for energy.