President Donald Trump has appeared to acknowledge he is under investigation in the inquiry into alleged Russian meddling in the US election.

In a tweet, the president also seemed to accuse the US deputy attorney general of pursuing a “Witch Hunt”.

He said: “I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director!”

Deputy Attorney General Rod Rosenstein wrote a memo the White House used to justify the firing of the ex-FBI chief.

Mr Rosenstein took over the investigation into whether Russia tried to tip the US election in favour of Mr Trump after Attorney General Jeff Sessions recused himself in March.

The deputy attorney general later appointed Special Counsel Robert Mueller to lead the inquiry.

The FBI and Congress are both looking at whether Trump campaign officials colluded with the alleged Kremlin plot. The inquiries have yet to show evidence of collusion.

Mr Trump also tweeted on Friday morning: “After 7 months of investigations & committee hearings about my ‘collusion with the Russians,’ nobody has been able to show any proof. Sad!”

His tweets come as Mr Trump marks two years since announcing his plan to run for president.

Why is Mr Trump being investigated?

Mr Trump was not under investigation before Mr Comey’s firing, but reportedly is now facing scrutiny for obstruction of justice over the circumstances surrounding the ex-FBI chief’s sacking, according to US media.

Special Counsel Mueller was reportedly planning to interview intelligence officials on whether Mr Trump got rid of the FBI director, James Comey, in May to hamper an inquiry into his sacked national security adviser, Michael Flynn.

Mr Comey, who had been leading one of several Russia inquiries, testified to Congress last week that the president had pressured him to drop an inquiry into links between Mr Flynn and Russia.

Mr Flynn was forced out in February after he misled the vice-president about his conversations with Russia’s ambassador before Mr Trump took office.

The White House has said the president “has never asked Mr Comey or anyone else to end any investigation, including any investigation involving General Flynn”.

Friday’s tweet marked the first time Mr Trump has publicly acknowledged he is under investigation.

Mr Comey said he was “sure” Mr Mueller was looking at whether Mr Trump had obstructed justice, but added that to his knowledge, the president had not tried to impede the Russia inquiry.

Mr Trump is unlikely to face criminal prosecution as a sitting president, but obstruction of justice could be grounds for impeachment.