A lawyer for White House adviser Jared Kushner has pushed back after a Senate committee said he had not been fully forthcoming in its probe into Russian election interference.
Lawyer Abbe Lowell said Mr Kushner encouraged others in President Donald Trump's campaign to decline meetings with foreign people who "go back home and claim they have special access to gain importance for themselves".
The top Republican and Democrat on the Senate Judiciary Committee wrote a letter to Mr Kushner, who is Donald Trump's son-in-law, on Thursday asking him to provide additional documents to the committee, including one sent to him involving WikiLeaks and a "Russian backdoor overture and dinner invite".
The senators noted they have received documents from other campaign officials that were copied to or forwarded to Mr Kushner, but which he did not produce. Those include "September 2016 email communications to Mr Kushner concerning WikiLeaks".
It was revealed this week that Mr Trump's eldest son, Donald Trump Jr, corresponded with WikiLeaks that month and later sent an email to several Trump campaign advisers to tell them about it.
Mr Lowell wrote Friday to Senators Chuck Grassley and Dianne Feinstein. He said the email from Donald Trump Jr referring to his contact with WikiLeaks was forwarded to Mr Kushner, but he did not respond.
Apparently referring to the email that the senators called a "Russian backdoor overture and dinner invite", Mr Lowell said that was part of an email chain that included biographies of various individuals.
Mr Lowell wrote that "there is a reference to one of these people suggesting an idea that somewhere, sometime (before the words 'Russia' or 'Putin' were politically charged or relevant in the campaign), someone thought candidate Trump should visit Russia".
Mr Lowell goes on to quote Mr Kushner's response to that email: "Pass on this. A lot of people come claiming to carry messages. Very few we are able to verify. For now I think we decline such meetings. Most likely these people go home and claim they have special access to gain importance for themselves. Be careful."
The senators' request is part of the panel's probe into the Russian election meddling and whether the Trump campaign was involved.
The Judiciary committee is one of three congressional committees looking into the issue, along with the Senate and House intelligence panels. The committees have separately requested and received thousands of documents from people associated with the Trump campaign, and have interviewed dozens of individuals. Department of Justice special counsel Robert Mueller is also looking into the meddling.
In the letter to Mr Kushner, the senators noted they had asked him to provide documents to, from, or copied to him "relating to" certain individuals of interest to investigators, but Mr Kushner responded that no emails had been found in which those individuals were sent emails, received emails, or were copied on them.
Mr Lowell replied that Mr Kushner had provided the Judiciary panel with the same documents he had provided the intelligence panels, believing that would be enough to satisfy the Judiciary request.
The Senate and House intelligence committees interviewed Mr Kushner in July. The Judiciary panel has also sought an interview with Mr Kushner, but his lawyers offered to make the transcripts available from the other interviews instead, according to the letters. Mr Grassley and Ms Feinstein say those panels have not provided them with those transcripts, and ask Mr Lowell to secure that access.
"I do not understand why these committees would not provide the transcripts to you, but we do not have those transcripts," Mr Lowell wrote, adding that it would be "duplicative" if the committees did not share their transcripts.