The first charges come just five months into the special counsel investigation. That suggests that it is progressing far more quickly than such probes – which can sometimes take a year or two before charges are brought – normally do.
Many of the President's closest and most senior aides have been interviewed for Mr Mueller's investigation, including Reince Preibus and Sean Spicer, both of which served in high-ranking positions in his White House before they were dismissed.
Mr Trump has refused to recognise the legitimacy of the probe, labelling a witch hunt and suggesting that it was being conducted to cover up for the Democrats' poor performance in the 2016 elections.
The charges that Mr Manafort and Mr Gates face are still unknown, according to the New York Times, which first reported the charges.
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