US President Donald Trump has ordered the expulsion of dozens of Russian diplomats and the closure of its consulate in Seattle.

Reuters reports he's taken the decision in the wake of the chemical attack in the UK earlier this month.

The news has emerged within hours of an interview with US porn star, who says she was threatened in 2011 to keep quiet about her sexual encounter with Donald Trump.

Stormy Daniels has appeared on CNN's 60 Minutes to break her silence on their alleged affair.