Donald Trump Jr has released private Twitter correspondence with anti-secrecy website Wikileaks after a US magazine revealed they had communicated shortly before his father’s election.
The Atlantic magazine revealed the organisation had asked Mr Trump Jr for co-operation and information.
The group published leaks of Clinton campaign emails during the election.
Mr Trump Jr’s lawyers handed the Twitter direct messages to congressional investigators.
The congressional inquiry is one of several looking into allegations of Russian collusion and meddling in the US election.
The largely one-sided transcripts show the president’s eldest son replied only a few times to a series of requests from Wikileaks.
In a series of Monday night tweets, Mr Trump Jr played down his contact with the group, referring to his “whopping 3 responses” which he said one of the congressional committees “has chosen to selectively leak. How ironic!”.
Messages show Wikileaks appeared to have first contacted Mr Trump Jr on 20 September, asking if he knew the origin of an anti-Trump website.
He replied the next day saying: “Off the record I don’t know who that is, but I’ll ask around. Thanks.”
The Atlantic alleges he then emailed senior officials including Steve Bannon, Kellyanne Conway and Mr Trump’s son-in-law Jared Kushner to tell them Wikileaks had made contact.
The correspondence between September 2016 and July this year shows Wikileaks urging his father to share their Clinton files; asking him to supply his tax returns to Wikileaks and advising him to challenge the result if he lost the election.
The Atlantic piece points out that while Mr Trump Jr didn’t reply to later messages, timestamps from tweets show instances where he and his father appear to have “acted on its requests” by mentioning or sharing Wikileaks stories shortly afterwards.
Wikileaks founder Julian Assange has criticised The Atlantic’s story.
He accuses it of selecting messages that were “edited” and failing to show the full context of the conversations.
Mr Assange also said the messages were part of the group’s promotional efforts. “Wikileaks can be very effective at convincing even high-profile people that it is their interest to promote links to its publications,” Mr Assange said in a tweet.
Donald Trump Jr’s lawyer Alan Futerfas told the magazine: “Over the last several months, we have worked co-operatively with each of the committees and have voluntarily turned over thousands of documents in response to their requests.”
“Putting aside the question as to why or by whom such documents, provided to Congress under promises of confidentiality, have been selectively leaked, we can say with confidence that we have no concerns about these documents and any questions raised about them have been easily answered in the appropriate forum.”