President Donald Trump's accusation that his predecessor ordered his phones to be tapped is "simply false", Barack Obama's spokesman has said.
Kevin Lewis said that "neither President Obama nor any White House official ever ordered surveillance on any US citizen".
Mr Trump had tweeted: "Terrible! Just found out Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism!"
He gave no details to back the claim.