Barack Obama livid over Donald Trump accusation he tapped Trump Tower

Former President Barack Obama was furious after US President Donald Trump's accusation he tapped phones and communications from Trump Tower ahead of the 2016 election.

"Terrible! Just found out that Obama had my 'wires tapped' in Trump Tower just before the victory," Trump wrote on Twitter on Saturday 5 March, adding "this is Nixon/Watergate. Bad (or sick) guy!"

The tweet storm was said to have made Obama livid over the accusation that he tapped Republican campaign offices, according to The Wall Street Journal on 7 March, which spoke with people familiar with Obama's thinking. Trump maintains an election war room in the tower. Obama believes that Trump was questioning both his integrity and the office of the president, the sources said.

The Department of Justice, under the Obama administration, did obtain a special Foreign Intelligence Surveillance Act (Fisa) warrant in October 2016, according to the BBC, to investigate transfers of money from Russia. The investigation included three Trump associates.

On Sunday, former director of national intelligence James Clapper denied any wiretap was made on Trump or Trump Tower. FBI director James Comey has also reportedly contacted the Department of Justice to urge that it publicly refutes Trump's claims – which suggest the law enforcement agency tapped his phones illegally – since there was no warrant.

White House officials suggest that Trump came to believe his phones were tapped after reading right-wing media reports speculating Obama had launched a "silent coup" against Trump.

No other president has ever accused another of breaking the law and Obama has not come out publicly to speak out against Trump's claims.

"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," Kevin Lewis, an Obama spokesman, told the WSJ. "As part of that practice, neither President Obama nor any White House official ever ordered surveillance on any US citizen. Any suggestion otherwise is simply false."

Obama's former press secretary told ABC News on Sunday that the president doesn't have the power to unilaterally wiretap an American in the US.

"If the FBI decided to use their wiretapping authority in the context of the counterintelligence or criminal investigation," Josh Earnest said on ABC's This Week. "It would require FBI investigators, officials at the Department of Justice going to a federal judge, and making a case, and demonstrating probable cause to use that authority to conduct the investigation. That is a fact," he said.