The Trump administration is hitting more than 50 vessels, shipping companies and trade businesses with sanctions in the latest bid to turn up the pressure on North Korea over its nuclear programme, US officials said.

President Donald Trump is set to announce the action Friday at the Conservative Political Action Conference, followed by a public announcement from the US treasury.

One official said Mr Trump will call it “the largest ever set of new sanctions” on the North. The measures are targeted at sources of fuel and cash for Kim Jong Un’s regime.

The announcement comes as South Korea hosts the Winter Olympics, an occasion the two Koreas have used as an opportunity to try to restart talks.