President Donald Trump lashed out at James Comey and the FBI on Saturday, after The New York Times reported that the intelligence agency launched an investigation into whether he was working for the Russian government.

In a series of tweets, Mr Trump claimed he has been “far tougher on Russia” than previous presidents Barack Obama, George W Bush and Bill Clinton, and suggested he had taken a tougher stance than any other president.

He also returned to his accusation, without evidence, that the investigation led by Robert Mueller into Russian interference was an “insurance policy” to stop his presidency, organised by the Democratic Party.

He described Mr Comey, former acting-FBI director Andrew McCabe and other former FBI officials as “some of the losers that tried to do a number on your president.”

The New York Times reported that the FBI launched a counterintelligence investigation into Mr Trump in the days following his firing of Mr Comey in May 2017.

Officials were concerned that the president’s actions could be a threat to national security and wanted to determine whether Mr Trump was knowingly helping Russia, according to former law enforcement officials.

It is unclear what conclusion the inquiry came to, as it was reportedly taken over by Mr Mueller when he was appointed to lead a broader investigation into Russia interference in the 2016 presidential election and possible collusion with the Trump campaign.

It is also unknown whether the counterintelligence inquiry is still part of the Mueller investigation, which is expected to conclude this year.

There is currently no public evidence that Mr Trump secretly contacted or took direction from Russian government officials.

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White House press secretary Sarah Huckabee Sanders described the Times’ report as “absurd” and repeated Mr Trump's claim that the president had not cooperated with Russia.

“Unlike President Obama, who let Russia and other foreign adversaries push America around, President Trump has actually been tough on Russia,” she said.

It was known that the FBI had begun a criminal investigation into Mr Trump over whether he had obstructed justice by firing Mr Comey, but the counterintelligence aspect of the inquiry was not publicly-known.

The president reportedly caught the attention of FBI counterintelligence agents during the 2016 election, when he called on Russia to hack Hillary Clinton’s emails, according to The New York Times.

Agents were also said to have been concerned by his praise for Vladimir Putin on the campaign trail.

Multiple Trump officials have already been charged or convicted as part of the Mueller investigation.

Mr Trump’s former campaign chairman Paul Manafort and former lawyer Michael Cohen have both been convicted for illegal activity during the 2016 campaign.