Updated | Trump urges Congress to probe Obama phone-tapping allegations

US President Donald Trump has called on Congress to investigate his allegations that his predecessor Barack Obama had ordered his phones to be tapped during the election campaign.

“Reports concerning potentially politically motivated investigations immediately ahead of the 2016 election are very troubling,” White House press secretary Sean Spicer said in a series of tweets. “President Trump is requesting that as part of their investigation into Russian activity, the congressional intelligence committee exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016.”

He added: “Neither the White House nor the President will comment further until such oversight in concluded.”

On Saturday morning, Trump launched a series of tweets that began at 5:35am. In one he wrote: “Terrible! Just found out that Obama had my ‘wire tapped’ in Trump Tower just before the victory. Nothing found. This is McCarthism!”

He followed up with tweets that claimed Obama had defied a court rejection to tap his office, and invited a “good lawyer” to make a case against the alleged process.

He then compared the alleged surveillance to Watergate – the scandal in which a 1972 break-in at the Democratic National Committee headquarters led to revelations of crime and cover-up at the highest levels of government and ultimately to the resignation of President Richard Nixon.

“How low has President Obama gone to tapp [sic] my phones during the very sacred election process,” Trump tweeted. “This is Nixon/Watergate. Bad (or sick) guy!”

Obama’s spokesperson Kevin Lewis insisted that any suggestion that the former President or  his staff had “ordered surveillance on any US citizen” was false.

“A cardinal rule of the Obama administration was that no White House official ever interfered with any independent investigation led by the Department of Justice,” he said in a statement. “As part of that practice, neither President Obama nor any White House official ever ordered surveillance on any US citizen. Any suggestion otherwise is false.”

Under US law, a federal court would have to have found probable cause that the target of the surveillance is an “agent of a foreign power” in order to approve a warrant authorizing electronic surveillance of Trump Tower.

Trump did not offer any evidence to back up his allegations, but it has been speculated that his comments were prompted by stories circulating in the rightwing press, including one that claimed Obama is planning a “silent coup” against Trump.

Critics have dismissed the allegations as a move designed to deflect attention from investigations of Trump’s ties to Russia. This week, it emerged that his attorney general, former Alabama senator Jeff Sessions, failed to tell senators about two meetings wit the Russian ambassador to the US last year.

Last month, Trump’s national security advisor Michael Flynn was forced to resign over conversation with the ambassador and misleading statements about them to vice-president Mike Pence.