US president Donald Trump's son-in-law and adviser Jared Kushner has returned to Capitol Hill for a second day of private meetings with congressional investigators.
The closed-door conversation will take place between Mr Kushner and members of the House Intelligence Committee.
On Monday, Mr Kushner answered questions from staff on the Senate's intelligence panel, acknowledging four meetings with Russians during and after Mr Trump's victorious White House bid, and insisting he had "nothing to hide."
He said later: "All of my actions were proper."
Separately, the Senate Judiciary Committee issued a subpoena to compel the testimony of Paul Manafort, the Trump presidential campaign chairman who, along with Mr Kushner, attended a Trump Tower meeting last year which has invited congressional scrutiny.
A quiet insider who generally avoids the spotlight, Mr Kushner, who is married to the president's daughter Ivanka, is the first top Trump lieutenant to be quizzed by the congressional investigators probing Russian meddling in the 2016 presidential election.
Hours before the Senate meeting, Mr Kushner released an 11-page statement that was billed as his remarks to both the Senate and House committees.
In it, he acknowledged his Russian contacts during the campaign and then the following weeks, in which he served as a liaison between the transition and foreign governments.
He described each contact as either insignificant or routine and said the meetings, along with several others, were omitted from his security clearance form because of an aide's error.
Mr Kushner cast himself as a political novice learning in real time to juggle "thousands of meetings and interactions" in a fast-paced campaign.
"Let me be very clear," Mr Kushner said later at the White House, "I did not collude with Russia, nor do I know of anyone else in the campaign who did so."
Mr Kushner's statement was the first detailed defence from a campaign insider responding to the controversy that has all but consumed the first six months of Mr Trump's presidency.
US intelligence agencies have concluded that Russia sought to tip the 2016 campaign in Trump's favour.
Congressional committees, as well as a Justice Department special counsel, are investigating whether Trump associates coordinated with Russia in that effort and whether the president has sought to hamper the investigations.
Mr Kushner said he "will continue to cooperate as I have nothing to hide".
Mr Trump watched on TV as Mr Kushner made his appearance outside the West Wing and "thought Jared did a great job", said White House spokeswoman Sarah Huckabee Sanders.
She said his House testimony on Tuesday would show "what a hoax this entire thing is".
Mr Trump also took aim at the top Democrat on the House intelligence panel, California representative Adam Schiff, calling him "sleazy" in a tweet and saying he "spends all of his time on television".
The Democrat said on CBS's Face the Nation on Sunday that he has a "great many questions" for Mr Kushner.
Mr Schiff responded by tweeting that Mr Trump watches TV too often and his "comments and actions are beneath the dignity of the office".
Earlier, a spokesman for Russian president Vladimir Putin said a meeting between Mr Kushner and the chairman of a Russian bank did not occur on Kremlin orders.
The meeting in December between Mr Kushner and Vneshekonombank head Sergei Gorkov took place at the request of Sergei Kislyak, then the Russian ambassador, according to the White House adviser.
Vneshekonombank is a state-owned development bank.
A spokesman for Mr Manafort said the longtime Trump associate met bipartisan staff of the Senate intelligence committee on Tuesday morning.
Spokesman Jason Maloni said Mr Manafort "answered their questions fully".
Mr Manafort has been under scrutiny about his participation in the June 2016 meeting with a Russian lawyer at Trump Tower.
That meeting was described to the president's son Donald Trump Jr as part of a Russian government effort to aid the Trump campaign against his Democratic rival, Hillary Clinton.
Mr Manafort led the Trump campaign for several months before being forced to resign in August 2016.