The US justice department has reportedly opened a criminal inquiry into the origins of the investigation into Russian interference in the 2016 election, a move that would raise concerns that Donald Trump and his allies may be using the powers of the government to go after their opponents.

The development, first reported by the New York Times, comes as Trump is already facing an impeachment inquiry examining whether he withheld military aid to pressure the president of Ukraine to launch an investigation of former vice-president Joe Biden and his son Hunter. Biden is considered a frontrunner in the Democratic presidential primary race ahead of the 2020 election.

William Taylor, the acting US ambassador to Kyiv, this week provided congressional committees conducting impeachment hearings a detailed account of how Trump repeatedly sought to make a summit meeting and military aid to Ukraine conditional on its government launching investigations into the president’s political opponents.

In a fresh blow to Trump on Friday, lawyers for former national security advisor John Bolton were reportedly in talks about testifying in the impeachment inquiry. According to testimony from Fiona Hill, Trump’s former advisor on Russia and Europe, Bolton had been so disturbed by the effort to pressure to Ukraine that he had described it as a “drug deal”.

The US attorney general, William Barr, launched a review earlier this year to investigate Trump’s complaints that his campaign was improperly targeted by US intelligence and law enforcement agencies during the 2016 election.

Now that review has reportedly shifted to a criminal inquiry. It is unclear what potential crimes are being investigated, but the designation as a formal criminal investigation gives prosecutors the ability to issue subpoenas, potentially empanel a grand jury and compel witnesses to give testimony and bring federal criminal charges.

Democrats and some former law enforcement officials say Barr is using the justice department to chase unsubstantiated conspiracy theories that could benefit the Republican president politically, undermine the former special counsel Robert Mueller’s Russia investigation, and distract public attention from the impeachment inquiries.

As part of his inquiry, Barr has asked Australian and British justice officials for assistance and visited Italy twice, meeting intelligence agents in Rome in August and September to learn more about people mentioned in Mueller’s report.

The chairmen of the House judiciary committee, Jerry Nadler, and the House intelligence committee, Adam Schiff, which are leading the impeachment inquiry, said in a statement late on Thursday that the reports “raise profound new concerns” that Barr’s justice department “has lost its independence and become a vehicle for President Trump’s political revenge”.

“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 congressman Adam Schiff, chair of the House Intelligence committee and Jerry Nadler, chair of the House Judiciary committee, said.

Some of Trump’s allies, however, welcomed the reports. “If true, this shows Bill Barr is doing EXACTLY his job: following the facts Those who damaged America and broke the law to spread this hoax are about to face accountability,” Republican congressman Mark Meadows tweeted.

Months into his presidency, Trump fired James Comey, the FBI director who was leading the investigation into Russian meddling in the 2016 election, a shocking decision that drew comparisons to the Watergate-era “Saturday Night Massacre”.

Comey, as well as other top former law enforcement and intelligence officials are frequent targets of Trump’s ire and he has repeatedly assailed a “deep state” determined to thwart him.

Mueller’s investigation shadowed Trump’s presidency for nearly two years and outraged the Republican president, who cast it as a politically motivated “witch-hunt”.

Mueller’s investigation found that Moscow interfered in the 2016 election to help Trump, and led to criminal convictions of several former campaign aides. But Mueller concluded that he did not have enough evidence to establish a criminal conspiracy with Russia.

Barr appointed the Connecticut state attorney, John Durham, to lead the review of whether US intelligence and law enforcement agencies acted properly when they examined possible ties between the Trump campaign and Russia.

According to the New York Times, deeming the inquiry a “criminal” matter gives Durham the power to “subpoena for witness testimony and documents, to convene a grand jury and to file criminal charges”.

The justice department has said Trump recently made several calls at Barr’s request to foreign leaders, including the Australian prime minister, Scott Morrison, to help the attorney general with the Durham investigation.

Barr also traveled with Durham to Italy in August and September, and the two met with Italian intelligence officials to seek information about the activities of FBI agents assigned there, the Italian prime minister, Giuseppe Conte, said on Wednesday.

The White House did not immediately respond to a request for comment.