US President Donald Trump has repeatedly insisted the European Union is taking advantage of the US through unfair trade barriers.
European steel and aluminium exports have already been slapped with 25% tariffs and the US has threatened to target other products worth $21 billion including cars and aviation. The EU, meanwhile, has called for a de-escalation but declared itself ready to retaliate if needed.
Euronews takes a closer look at the trading relationship between the two allies.
The trade balance — the difference between imports and exports — for goods is indeed vastly in favour of the European Union. In fact, the US is the main partner for European exports, while it is the EU's second largest partner for imports.
Over the last decade, the EU's trade surplus with the US has doubled from €65.1 billion in 2008 to €139.1 billion last year.
Germany was the EU member state that exported the most to the US last year, while the UK was the biggest importer of American commodities.
What are the main commodities?
The main products the US and EU trade are machinery and vehicles, chemicals and other manufactured goods which include textiles, pharmaceuticals, optical and medical instruments among others.
When it comes to services, the picture is a lot murkier as EU and US statistics differ widely.
In a 2017 paper, Eurostat — the European Commission's official statistics provider — described the variations as "asymmetries" stemming from "different concepts and classifications applied in the compilation of trade statistics".
It flagged for instance that although the EU published €221.7 billion of services exports to the US in 2015, the US published imports of only €155.7 billion from the EU.
How does that compare to other trading relationships?
The EU is far from the only major entity, the US has a trade deficit with. While it posted a slight trade surplus with Canada last year, it recorded deficits with Japan, Mexico and China.
The EU once again fared better, registering a slightly bigger trade surplus with Canada and much smaller deficits with China and Japan.