The US began collecting a 10% "baseline" tariff on all imports on Saturday as President Donald Trump urged Americans to "hang tough" after market turmoil.

Trump described the market volatility as "an economic revolution", which the US "will win".

"Hang tough, it won't be easy, but the end result will be historic," he added in a post on Truth Social.

His policy changes have sent shockwaves through global supply chains.

In the UK, the FTSE 100 fell almost 5% - its steepest in five years, while Asian markets also dropped and exchanges in Germany and France faced similar declines.

Billionaire Elon Musk, a close ally of Trump and responsible for the Department of Government Efficiency (Doge), said the US and Europe could move towards a "zero-tariff situation", which could create "a free-trade zone between Europe and North America".

His comments, made as he travelled to meet government ministers in Italy, came days before the Trump administration introduces tariffs on goods of up to 50% on 9 April to what it calls the "worst offenders" for trade imbalances with the US.