Democrats accused President Donald Trump on Friday of using the U.S. Justice Department as a political tool after it opened a criminal probe into its own handling of the investigation into alleged Russian interference in the 2016 election. 

News of the inquiry, which implied wrongdoing by justice officials in the previous administration of Barack Obama, leaked late Thursday as the White House struggled to push back against a Democratic-led impeachment investigation targeting the Republican president. 

The inquiry could further muddy the political waters in Washington, raising questions about the now-ended Russia investigation led by Special Counsel Robert Mueller that saw 34 individuals indicted and eight convictions, including top members of Trump's 2016 election team.

Trump's Republican allies have sought to drown the impeachment probe in a pool of invective and counter-probes, forcibly shutting down one witness interview and demanding an investigation of the impeachment effort's leader, Democrat Adam Schiff. 

On Friday Republicans said the newly disclosed Justice Department inquiry could shore up the president's longstanding claim that the Mueller investigation was a "witch hunt" based on "fake news." 

"The point of the investigation is to make sure the DoJ and FBI under the Obama administration in 2016 wasn't being used as a tool to influence the elections," said Trump advisor Kellyanne Conway on Fox News. 

"Don't we have a right to know if... they were or were not subverting justice and trying to interfere with the elections?" she said.

'Profound concerns'  

But Democrats said it was a clear effort by Trump-allied Attorney General Bill Barr to shift attention from the impeachment probe, which has accumulated strong evidence that Trump abused his office in pressuring Ukraine to help his 2020 re-election campaign. 

The latest inquiry raises "profound new concerns that the Department of Justice under Attorney General William Barr has lost its independence and become a vehicle for President Trump's political revenge," said Schiff and another senior House Democrat, Jerry Nadler, in a statement.

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"If the Department of Justice may be used as a tool of political retribution or to help the president with a political narrative for the next election, the rule of law will suffer new and irreparable damage." 

Democratic Senator Mark Warner said Barr needs to explain the new inquiry to Congress. 

"Mr. Barr's 'investigation' has already jeopardized key international intelligence partnerships. He needs to come before Congress and explain himself," Warner said. 

The Justice Department did not respond to requests for comment.