German leaders have reacted angrily to proposed new American sanctions on Russia they say target Moscow’s new gas pipeline to Europe, threatening retaliation if the measures harm the European economy.

The stand-off comes amid already strained relations with the US over Donald Trump’s aggressive rhetoric and provoked accusations that America was trying to promote its own gas exports to Europe by blocking Russia.

The result is a rumbling threat of a new energy war and a breakdown in trans-Atlantic unity against Russian aggression.