US President Donald Trump expectedly took to Twitter shortly after his former campaign manager Paul Manafort was indicted as part of special counsel Robert Mueller's investigation into Russian interference in the 2016 election and possible collusion between the Trump campaign and the Kremlin. Twitter, on the other hand, couldn't help roasting Trump over his "scared" response as the investigation heats up.

Early Monday (30 October) morning, Trump fired off a pair of tweets after news broke that Manafort and his former business partner Rick Gates were charged with 12 counts including conspiracy against the United States, tax evasion and money laundering.

The 31-page indictment was unsealed on Monday morning as the first one from Mueller's probe following much anticipation and speculation over the weekend. A separate indictment unsealed on the same day revealed that George Papadopoulos, a former Trump campaign aide, pleaded guilty to lying to FBI investigators about conversations he had with a foreign professor regarding thousands of emails that allegedly contained "dirt" on Hillary Clinton.

Trump, however, continued to push back against the Russia probe and quickly defended against the indictments saying they were not related to his campaign.

"Sorry, but this is years ago, before Paul Manafort was part of the Trump campaign. But why aren't Crooked Hillary & the Dems the focus?????" Trump tweeted. "....Also, there is NO COLLUSION!"

As intense speculation surrounded the content of the Mueller probe indictments over the weekend, Trump hit back at reports and once again slammed the investigation as a "witch hunt" in a series of fiery tweets.

"Never seen such Republican ANGER & UNITY as I have concerning the lack of investigation on Clinton made Fake Dossier (now $12,000,000?), the Uranium to Russia deal, the 33,000 plus deleted emails, the Comey fix and so much more," Trump wrote on Sunday. "Instead they look at phony Trump/Russia 'collusion', which doesn't exist. The Dems are using this terrible (and bad for our country) Witch Hunt for evil politics, but the R's are now fighting back like never before.

"There is so much GUILT by Democrats/Clinton, and now the facts are pouring out. DO SOMETHING!"

Twitter revelled in Trump's "anxious" posts and proceeded to mock the president over the probe saying "it is just the beginning".

"Trump is so scared now that he and his friends are heading to prison. It's Mueller Time!" Dr Eugene Gu tweeted. "Grab some popcorn. This is going to be quite the show. The ratings will be huge."

One Twitter user questioned: "If Trump/Russia is phony, then shouldn't we embrace the investigation that we can all see the truth come out?"

Another said: "The Trump tirades against Clinton amidst the #TrumpRussia investigation show a man that is scared and aboard a sinking, burning ship."

"Watching you squirm over the next few months is going to be f**king delightful," one person said.

President Donald Trump took to Twitter to hit back at the ongoing Mueller probe and Twitter couldn't stop mocking him for it Chip Somodevilla/Getty Images