President Donald Trump on Thursday dismissed reports that he was being investigated for obstruction of justice, suggesting online that such allegations have been cooked-up to replace accusations that his presidential campaign colluded with the Russian government during the 2016 election.

“They made up a phony collusion with the Russians story, found zero proof, so now they go for obstruction of justice on the phony story. Nice,” Trump wrote on Twitter Thursday morning. In a subsequent post, Trump attacked those investigating him, calling them "very bad an conflicted people," although he did not specify if he was referring to the Congressional probes into hit 2016 campaign or the special prosecutor’s.

"You are witnessing the single greatest WITCH HUNT in American political history – led by some very bad and conflicted people! #MAGA," Trump wrote.

On Wednesday, The Washington Post reported that special counsel Robert Mueller, charged with leading an independent Russia investigation, had expanded that investigation to examine whether the president committed obstruction of justice.

That probe reportedly includes not only Trump’s conversations with former FBI Director James Comey, in which the president allegedly asked Comey to drop the bureau’s investigation into former national security adviser Michael Flynn, but also interactions between Trump and Director of National Intelligence Dan Coats, CIA Director Mike Pompeo and NSA Director Mike Rogers.

According to the Post report, the investigation into whether or not Trump sought to obstruct justice began shortly after he fired Comey, in line with private assurances that the former FBI director offered to the president that he was not under investigation at the time.

Trump has loudly denied that there was any collusion between his campaign and the Kremlin and has suggested that Comey lied about their interactions regarding Flynn. The president has suggested that there could be recordings of his interactions with Comey that would vindicate him, although he has yet to release those recordings or even confirm their existence.