Republicans have launched a bid to remove the Department of Justice official overseeing the Russia inquiry dogging Donald Trump's presidency.
House of Representatives conservatives have filed articles of impeachment in an effort to oust Deputy Attorney General Rod Rosenstein.
The articles were introduced by Representatives Mark Meadows and Jim Jordan, who accuse him of stonewalling their requests for information.
Mr Rosenstein denies the accusations.
The articles of impeachment, which were filed on Wednesday evening, criticise Mr Rosenstein for allegedly failing to comply with requests for documents relating to special counsel Robert Mueller's investigation into possible ties between the Trump campaign and Russia.
"Rod Rosenstein has been in charge of the Department of Justice as the agency has made every effort to obstruct legitimate attempts of congressional oversight," Mr Meadows said in a statement.
Mr Rosenstein has overseen the investigation since Attorney General Jeff Sessions recused himself last year.
Impeachment would have to be approved by a majority in the House and backed by two-thirds of the US Senate to convict Mr Rosenstein, which makes the plan a long shot.
Who is Rod Rosenstein?
Within weeks of becoming deputy attorney general in April 2017, Mr Rosenstein found himself in controversy after a memo he wrote was cited as the reason for President Trump's decision to fire FBI chief James Comey, who was investigating Russia's alleged interference in the 2016 US elections.
Earlier this month, the Department of Justice charged 12 Russian intelligence officers with hacking Democratic officials during the 2016 vote.
Although Mr Rosenstein has said there is no evidence they "altered the vote count or changed any election result", the announcement came just before Mr Trump's controversial summit with President Vladimir Putin in Helsinki.
BBC North America reporter Anthony Zurcher
Two of the most conservative members of the House of Representatives have their press release and flurry of media coverage for introducing articles of impeachment against Deputy Attorney General Rod Rosenstein. That's probably all they will get.
The motion, as introduced, is unlikely to see any kind of a vote. House Speaker Paul Ryan, along with many other Republicans, don't want it. They know a real push for impeachment would tear their party asunder.
Even if it does get a vote, and even if Mr Rosenstein is impeached, two-thirds of the Senate would have to support removing him after a trial in the chamber. The chances of that - which would require a significant number of Democrats in favour - are less than zero.
That doesn't mean those who want Robert Mueller's Russia investigation to continue unimpeded should breathe easy, however. The president might claim that the impeachment resolution shows Mr Rosenstein is too embattled to continue his duties and replace him with someone who would clip the special counsel's wings.
In April Mr Trump was reportedly itching to swing the axe on his deputy attorney general. Now, Jim Jordan and Mark Meadows could be helping to sharpen the president's blade.
What is the Mueller investigation?
President Trump's campaign team has been accused of colluding with Russia to influence the outcome of the presidential election.
In 2016, US intelligence agencies concluded that Russia had used a state-authorised campaign of cyber attacks and fake news stories planted on social media in an attempt to turn the election against Hillary Clinton.
Thirty-two people have now been indicted, including four members of Mr Trump's campaign team and 25 Russians.
Both Mr Trump and Russia have denied the allegations, with Mr Trump repeatedly describing the investigation as a "witch hunt".