The House intelligence panel inquiry will scrutinise contacts between Donald Trump's presidential campaign and Moscow, members confirmed.
The White House denies any improper behaviour during the election campaign.
The justice department has confirmed new Attorney General Jeff Sessions had conversations with Russia's ambassador during the presidential campaign.
The FBI and the Senate intelligence committee are also looking into claims of Russian meddling in the US election.
Russia has previously denied the allegations.
How much did they know? Analysis by Tulip Mazumdar, BBC News, Washington
The Russia question is refusing to go away for President Trump.
President Trump has denied any improper behaviour during the election campaign
This House intelligence committee, which has been investigating Russia for many years, says it will expand its inquiries to include Russian activities during the election and "leave no stone unturned".
The FBI and the Senate intelligence committee are already investigating Russian interference during the election.
It has already been established by the CIA and others that Mr Putin's government did make a concerted effort to help elect Donald Trump and to discredit his opponent Hillary Clinton.
But a key question remains - how much did the Trump campaign know about this?
President Trump and his team have repeatedly denied any knowledge of his campaign having contact with Russian officials in the run up to the election.
The panel said in a statement that its Republican chairman, Devin Nunes, and Democratic Congressman Adam Schiff had agreed to the investigation.
It will seek answers to the following questions:
- "What Russian cyber activity and other active measures were directed against the United States and its allies?"
- "Did the Russian active measures include links between Russia and individuals associated with political campaigns or any other U.S. Persons?"
- "What was the U.S. Government's response to these Russian active measures and what do we need to do to protect ourselves and our allies in the future?"
- "What possible leaks of classified information took place related to the Intelligence Community Assessment of these matters?"
Until now, Republican senators had been reluctant to agree to Democratic Party demands for the inquiry.
President Trump has been dogged by questions about his advisers' ties to Moscow since the campaign. The White House has strongly denied the claims.
The Associated Press news agency reports that White House lawyers instructed Mr Trump's staff on Tuesday to preserve materials that could be connected to Russian interference in November's election.
Michael Flynn (second left) was pictured dining with Russian leader Vladimir Putin (second right) in December 2015
Senate Democratic leader Chuck Schumer said last week: "There is real concern that some in the administration may try to cover up its ties to Russia by deleting emails, texts and other records that could shine a light on those connections."
The US intelligence community concluded that alleged Russian hacking of Democratic organisations was carried out to help Mr Trump defeat Democrat Hillary Clinton.
Mr Trump's National Security Adviser, Michael Flynn, was fired last month after he misled the White House about his conversations with the Russian ambassador to the US, allegedly regarding sanctions against Moscow.
In a separate development, the justice department said on Wednesday that Mr Sessions had had two conversations with the Russian ambassador during the presidential campaign:
- One was an office visit that happened when Mr Sessions was a member of the Senate Armed Services committee
- The other occurred in a group setting with other ambassadors
Sergei Kislyak has been Russia's ambassador to Washington since 2008.
The White House has so far made no comment on the issue.
Mr Schiff, the top Democrat on the House intelligence committee, said that if the reports were accurate Mr Sessions must withdraw from the FBI investigation into claims of Russian meddling in the US election.
As attorney general, Mr Sessions oversees that FBI.