The probe into Russia's alleged interference in the 2016 election has moved into a new and potentially more dangerous phase for US President Donald Trump, with the use of a grand jury by special counsel Robert Mueller.

Media reports say its focus is a meeting last year between the President's son and a Russian lawyer apparently offering information damaging to Mr Trump's rival Hillary Clinton. Reports say the Federal Bureau of Investigation is also widening its probe to include the global business empire the US President nominally handed over to his sons.

Mr Trump himself went to West Virginia, where he told supporters at a rally that the probe is a "total fabrication". He said: "Most people know there were no Russians in our campaign; there never were. We didn't win because of Russia; we won because of you."

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