WASHINGTON (AP) — President Donald Trump appeared to confirm Friday that he is under investigation for obstruction of justice, claiming that he is being investigated for firing FBI Director James Comey by the man who told him to do it.

It wasn’t clear whether the president was basing his tweet on direct knowledge that he is under investigation, or on reports this week that special counsel Robert Mueller is examining whether the president obstructed justice by firing Comey last month amid the ongoing Russia investigation.

Mueller was appointed as special counsel to investigate Russian involvement in the 2016 presidential election and possible collusion by Trump campaign associates with the Russians, but there has been no indication that Mueller told Trump to fire Comey.

“I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt,” the president wrote in his tweet.

In another tweet earlier Friday, Trump writes, “After 7 months of investigations & committee hearings about my ‘collusion with the Russians,’ nobody has been able to show any proof. Sad!”

Deputy Attorney General Rod Rosenstein submitted a widely circulated memo to the president last month raising concerns over Comey’s performance, but Trump later asserted that he had already made the decision himself to fire Comey.

The White House confirmed that Mueller was among the candidates Trump interviewed to replace Comey. A day later, Rosenstein appointed Mueller, who was at the helm of the FBI during the Sept. 11 attacks, as special counsel.

Friday’s tweets are the latest in a week of angry social media responses by the president over a report by The Washington Post that Mueller was looking into whether Trump obstructed justice.

In a series of statements on Twitter Thursday, Trump repeated his assertion that Mueller’s investigation into Russian interference in the 2016 campaign is a “WITCH HUNT” based on the “phony” premise of possible collusion between Russia and a cadre of Trump campaign associates.