After three years spent trying to deter Russia from destroying Ukraine, European Union leaders grappled on Monday with how to respond to a major ally who appears determined to start a trade war or even seize part of their territory.

It's increasingly likely U.S. President Donald Trump will try to slap the European Union with tariffs. European leaders say they are ready to hit back, but the threat of a U.S.-EU trade war is shaking transatlantic relations.

President Donald Trump on Wednesday warned he would impose “high levels” of taxes, tariffs and sanctions on Russia unless Russian President Vladimir Putin strikes a deal to end the war in Ukraine, even as trade between the U.S. and Russia has become increasingly limited in recent years.

President Donald Trump has threatened to slap dozens of countries with specialized tariffs, along with taxes on imports that would affect every other nation. That could affect trillions of dollars in trade,

"There are no winners in trade wars. If … the U.S. starts a trade war, then the one laughing on the side is China," said the EU's foreign policy chief.

The European Union leaders on February 3 gathered in Belgium’s Brussels to discuss on ‘global uncertainties’ for the union. The meeting aimed to bolster union’s defences against Russia and how to handle US President Trump after his decision to impose tariffs.

EU leaders have vowed unity against Trump's tariffs as they gather in Brussels to discusses defence and security issues. View on euronews