Germany’s new foreign minister, Annalena Baerbock, has been caught a diplomatic vice days into the job, as US puts pressure on the coalition government in Berlin to vow to block the Nord Stream 2 pipeline in the event of Russia invading Ukraine. The controversial pipeline project, which runs from Ust-Luga in Russia to Lubmin in north-east Germany, is also likely to be the first test of the new German government’s unity of approach. Baerbock, the 40-year-old Green co-leader, has long opposed the near-complete giant pipeline, but the German coalition programme is silent on the issue, due to support for the project from the new German chancellor Olaf Scholz’s Social Democrats. As Nato and Europe prepared a deterrence package designed to frighten Russia off a military incursion into Ukraine, the Biden administration, with strong backing from the UK, Poland and Baltic States, is demanding that the pipeline be included as part of a wider sanctions package if Russia sends troops into Ukraine. It is expected that Germany will agree, but on conditions that are likely to be subject to negotiation within the government and reveal the degree to which Baerbock is forced to submit to Scholz’s control of foreign policy. Speaking in Paris on Thursday alongside the French foreign minister, Jean Yves Le Drian, Baerbock said: “The territorial integrity and sovereignty of Ukraine are non-negotiable for us. Russia would pay a high political and economic price for renewed violation of Ukrainian statehood.” In opposition, Baerbock said the pipeline only benefited the Putin regime, destabilised Ukraine, contradicted EU climate change targets and clashed with Europe’s geostrategic interests. Scholz has been more evasive on the subject, fully aware of the pipeline’s champions within the ranks of the SPD. The energy link is not only supported by former chancellor Gerhard Schröder, now chair of Nord Stream’s board of directors, but also the centre-left party’s branch in Mecklenburg-Vorpommern, where the local population hopes to draw economic advantages once gas starts running underneath the Baltic Sea. Scholz indicated that he would not leave it to his Green coalition partners to dictate his government’s language around Nord Stream 2. “The whole country is being watched by the world,” he said. “That’s why we as a government will act in unison – and that starts with the head of government.” “We have a very clear attitude: we want everyone’s borders to be respected,” Scholz told Die Welt newspaper on Wednesday. “Everyone understands that there will be consequences if that is not the case.” The new chancellor did not go as far as spelling out a threat to abandon the project. The Russian gas company Gazprom built the pipeline at a cost of €9.5bn (£8.1bn), overcoming objections from the US, Poland and Ukraine, and is now awaiting German regulatory certification, currently withheld on a legal technicality concerning Nord Stream’s independence as a transmission operator from Gazprom. When fully operational, the pipeline would transport 55bn cubic metres of gas to Germany every year, equivalent to about 15% of the EU’s total gas imports. The US in July backed off from taking sanctions against German firms involved in Nord Stream, but said if there was evidence of Russian efforts to use the pipeline or gas supplies as a way of forcing through political or wider economic concessions, they could return. “If Vladimir Putin wants to see gas flow through that pipeline, he may not want to take the risk of invading Ukraine,” the US national security adviser, Jake Sullivan, said on Tuesday after a conversation between Putin and US president Joe Biden. There is strong support for the measure in the US Congress. Baerbock also came under pressure from Poland on the issue ahead of a visit to Warsaw on Friday. “I will call on Chancellor Scholz not to give in to pressure from Russia and not to allow Nord Stream 2 to be used as an instrument for blackmail against Ukraine, an instrument for blackmail against Poland, an instrument for blackmail against the European Union,” the Polish prime minister, Mateusz Morawiecki, said on a visit to Rome. Even if sanctions are not imposed in the immediate future, the new German government will have to clarify whether it wants the pipeline to go ahead if the threat to Ukraine is lifted. It is not clear on what legal basis the pipeline, long presented by the previous German government as an economic project with virtually no geopolitical consequence, needs clearance under European Union energy competition laws. EU rules require “unbundling”, whereby companies producing, transporting and distributing gas within the EU are separate legal entities and a pipeline such as Nord Stream 2 can be used by third parties with a non-discriminatory and transparent pricing structure. The Nord Stream issue comes as part of the self-imposed pressure placed on the new German government to give a higher profile to human rights and values in foreign policy. With France resisting joining the diplomatic boycott of the Beijing Olympics, Baerbock said Germany would make its decision in conjunction with its European friends. France is to host the summer Olympics in 2024 and is reluctant to see the tournament become a victim of geopolitics. After her visit to Warsaw on Friday, Baerbock will travel to Liverpool for a UK-hosted meeting of G7 foreign ministers. The liberal Free Democratic Party (FDP), the third coalition partner in Germany’s “traffic light” government, has also positioned itself against the pipeline.