President Trump has signed off on sanctions against companies building a Russian natural gas pipeline to Germany that Congress fears will give the Kremlin dangerous leverage over America's European allies.

The sanctions, which are opposed by the European Union, were included in a sprawling defence spending bill that Mr Trump signed at a ceremony on Joint Base Andrews, an air force installation outside Washington.

They target companies building the nearly $11 billion Nord Stream 2 pipeline under the Baltic Sea with the aim of doubling deliveries of Russian natural gas to Europe’s leading economy, Germany.

US lawmakers have warned that the pipeline would enrich a hostile Russian government and vastly increase President Putin’s influence in Europe at a time of heightened tension across the continent.

Both houses of Congress overwhelmingly approved the sanctions, with the Senate voting on Tuesday to send the measure to Mr Trump’s desk.