US President Donald Trump has repeated assertions by his lawyer and advisor Rudy Giuliani that the alleged collusion between his 2016 election campaign and Russia would not be illegal.

“Collusion is not a crime, but that doesn’t matter because there was No Collusion (except by Crooked Hillary and the Democrats)!” Trump wrote on Twitter on Tuesday while making a reference to his rival in the 2016 presidential elections Hillary Clinton.

Collusion is not a crime, but that doesn’t matter because there was No Collusion (except by Crooked Hillary and the Democrats)! — Donald J. Trump (@realDonaldTrump) July 31, 2018

Then post is the latest to come from Trump and his inner circle against an ongoing investigation by special counsel Robert Mueller into alleged Russian interference in the 2016 elections. Trump has earlier denied any collusion with the Russians while calling the probe and the media hype around it a “witch hunt.”

Trump’s intensified attack on the probe comes as Mueller is to hear testimonies from former campaign chairman Paul Manafort this week, a first trial in the probe which many expect to really implicate Trump. Manafort, who is to face 18 charges, had pleaded not guilty. His business partner Rick Gates has pleaded guilty and is cooperating with the probe.

The Associated Press wrote a commentary endorsing Giuliani and Trump’s assertions that collusion is not a crime. However, it said if Mueller finds evidence that Trump's campaign cooperated with the Kremlin, there were laws that could lead to charges for the campaign over conspiracy, fraud and computer hacking, among others.

Lawyer of the US president Rudy Giuliani looks on before the US president announces his Supreme Court nominee in the East Room of the White House on July 9, 2018 in Washington, DC. (AFP photo)

Mueller has already accused the Russians of hacking into Democrats’ computers and stealing emails while trying to use the social media to stoke tensions in the 2016 elections.

Jay Sekulow, a member of Trump’s defense team, said that Trump and Giuliani were right to say that collusion with Russia, if there was any, was not a crime.

“It is not a violation of any rule, statute or regulation that we have seen after reviewing this case for a year. I think Bob Mueller will come to the same conclusion,” said Sekulow on Fox News on Tuesday.