The United States has warned that firms that have invested in Russia’s Nord Stream 2 gas pipeline to Germany were at the risk of sanctions, Reuters reported on Thursday. The US alleged that Moscow was using the project to divide Europe.

Nord Stream 2 is a pipeline project to transport natural gas from eastern Russia to northern Germany, where it would link up with infrastructure that carries fuel to Western Europe, reported CNBC. It would run 1,200 km, mostly under the Baltic Sea along the existing Nord Stream pipeline.

The US is opposed to the project because it will increase Europe’s reliance on Russia for gas supplies. US Deputy Assistant Secretary of State for Energy Diplomacy Sandra Oudkirk told Bloomberg that the US is also worried the pipeline could open ways for Russia to install undersea surveillance equipment in the Baltic Sea.

“That means that any pipeline project, and there are multiple pipeline projects in the world that are potentially covered, is at an elevated sanctions risk,” Oudkirk said.

An unidentified spokesperson for the US State Department told Reuters that the project would “undermine Europe’s overall energy security and stability” by providing Russia a tool for the political coercion of European countries, especially Ukraine. “Russia understands that this project is dividing Europe, and is using that to its advantage.”

On Wednesday, US President Donald Trump accused Germany of becoming “a captive of Russia”, while criticising Berlin for supporting a Baltic Sea gas pipeline deal with Moscow. German Chancellor Angela Merkel said that the project is a private commercial venture, not funded by German taxpayers, Reuters reported.