The EU has said it "strongly" regrets Donald Trump's surprise plan to double US tariffs on steel and aluminium in a move that risks throwing bilateral trade talks into chaos.

On Friday, the US president told a rally in the steel-making city of Pittsburgh that the tariffs would rise from 25% to 50%, claiming this would boost local industry and national supplies.

The European Commission told the BBC on Saturday that Trump's latest move on tariffs "undermines ongoing efforts" to reach a deal, warning about "countermeasures".

This also raises questions about the UK's zero tariff deal with the US on steel and aluminium which, although agreed, has not yet been signed.

UK steelmakers said the doubling of the tariffs is "yet another body blow" to the industry while a UK government spokesman said "we are engaging with the US on the implications of the latest tariff announcement and to provide clarity for industry".

The UK - which left the EU following the 2016 Brexit referendum - was the first country to clinch a trade deal with the US earlier this month.

In a statement sent to the BBC on Saturday, the European Commission, the EU's executive arm, said: "We strongly regret the announced increase of US tariffs on steel imports from 25% to 50%.

"This decision adds further uncertainty to the global economy and increases costs for consumers and businesses on both sides of the Atlantic.

"The tariff increase also undermines ongoing efforts to reach a negotiated solution.

"In good faith, the EU paused its countermeasures on 14 April to create space for continued negotiations," the statement said, warning the bloc "is prepared to impose countermeasures".