President Donald Trump on Thursday seemed to acknowledge an obstruction-of-justice investigation into his firing of James Comey as FBI director.

“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 tweeted Thursday morning.

The Washington Post reported Wednesday that the FBI’s investigation into Russian election interference expanded last month to include whether Trump tried to obstruct justice. It was not immediately clear who “they” referred to, but Trump has repeatedly blamed the news media and Democrats for investigations into whether his presidential campaign colluded with Russia to meddle in last year’s election.

Trump wrote in a follow-up tweet that he was the victim of a “witch hunt” and called the people behind the investigations “very bad and conflicted.”

"You are witnessing the single greatest WITCH HUNT in American political history - led by some very bad and conflicted people! #MAGA," Trump tweeted (using an acronym for "Make America Great Again").