Barack Obama's spokesman has denied allegations by Donald Trump that the former President ordered for his offices in New York to be “wiretapped” before the presidential election.
Speaking several hours after Mr Trump made the claims on Twitter, Kevin Lewis asserted that any suggestion Mr Obama or his staff had "ordered surveillance on any US citizen" was false.
He added that a “cardinal rule” of the Obama administration was that no White House official ever interfered in any Justice Department investigations, which are supposed to be conducted free of political influence.
“As part of that practice, neither Obama nor White House official ever ordered surveillance on any US citizen. Any suggestion otherwise is false,” Mr Lewis said.
The President made the allegations against his predecessor early on Saturday morning, tweeting: “Just found out that Obama had my 'wires tapped' in Trump Tower just before the victory. Nothing found. This is McCarthyism!”
Shortly afterwards, Mr Trump added: “Is it legal for a sitting President to be ‘wire tapping’ a race for president prior to an election? Turned down by court earlier. A new low!
"I'd bet a good lawyer could make a great case out of the fact that President Obama was tapping my phones in October, just prior to election!"
Mr Trump also suggested that Mr Obama was "sick", writing: "How low has President Obama gone to tapp [sic] my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!"
The President did not provide evidence that Mr Obama was responsible for surveillance on his property, and the White House did not immediately return requests for comment Saturday morning.
A former senior US official with direct knowledge of investigations by the Justice Department under the Obama administration denied there was any such investigation of Mr Trump or that his phones were tapped.
"This did not happen. It is false. Wrong," the former official said, adding that Mr Obama could not order this, and that it would have been taken to a judge by investigators, but investigators never did this.
The former deputy national security adviser under Mr Obama, Ben Rhodes, meanwhile tweeted that presidents cannot order wiretapping.
"No President can order a wiretap. Those restrictions were put in place to protect citizens from people like you," Mr Rhodes said in his Twitter post.
It is not the first time Mr Trump has attacked his predecessor, having waged a years-long "birtherism" campaign alleging Mr Obama was not a US citizen and had a fake birth certificate.
His tweets mark the President's latest controversial assertions in the back-and-forth over questions about whether his campaign made contact with Russians known to US intelligence.
