Thom Tillis, a Republican senator, has reiterated his vow to block Donald Trump’s nomination of Kevin Warsh from Fed chair until the criminal investigation into Jerome Powell, the current head of the central bank, is halted.The tech-heavy Nasdaq Composite fell 1.1pc to 23,438 points, while the Dow Jones Industrial Average declined nearly 1pc to 48,582 points.All three major US indexes have extended losses as investors respond to Kevin Warsh being nominated to lead the Federal Reserve.Gold also plunged, with ...