Donald Trump has vowed that people who pushed "evil" claims he colluded with Russia will be investigated after special counsel Robert Mueller found there had been no conspiracy with the Kremlin.

The US president said those making the allegations over his 2016 election conduct had been “treasonous” and done “very bad things”, adding that they "will certainly be looked at".

The White House went on the attack on Monday after claiming “complete exoneration” from Mr Mueller, despite the fact the special counsel himself did not clear Mr Trump over obstruction of justice.

Sarah Sanders and Rudy Giuliani, the president’s press secretary and lawyer, demanded the Democrats and “liberal media” who talked up collusion apologise in a message echoed by high profile supporters.

Lindsey Graham, the Republican senator close to the president, held a press conference to declare he wanted a new special counsel to investigate FBI and Justice Department officials who begun the probe into Mr Trump.