The whistleblowing website posted on Twitter a letter purportedly from the Senate Select Committee on Intelligence asking Assange to "make yourself available for a closed interview with bipartisan committee staff at a mutually agreeable time and location".
Assange has been holed up in the Ecuadorian embassy in London since June 2012, having been granted asylum, and later citizenship, by Ecuador.
The letter from Burr and Warner said: "As you are aware, the Senate Select Committee on Intelligence is conducting a bipartisan inquiry into Russian interference in the 2016 U.S. elections".
There have also been reports that Ecuador and Britain have reached, or are about to reach, a deal on ending the asylum for Assange.
Mark Warner. Wikileaks wrote on Twitter that its legal team is "considering the offer but testimony must conform to a high ethical standard".
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The recent replacement of Ecuadorian president Rafael Correa with Lenin Moreno, who has expressed concerns about the WikiLeaks founder, has suggested Assange's future in the embassy could be imperilled.
But because he breached bail conditions, he would be arrested by British police if he left the embassy.
Assange believes that would pave the way for extradition to the United States for the publication of a huge cache of USA diplomatic and military secrets on the WikiLeaks website.
Assange is now without internet access after clashing with the Ecuadorian government for his activities on social media during the U.S. and Spanish elections.
In the summer and fall of 2016, WikiLeaks published thousands of emails and documents from the Democratic National Committee's servers and from Hillary Clinton senior aide John Podesta, which were pilfered by Russian intelligence.
But according to Daily Beast reporting and special prosecutor Robert Mueller, Guccifer2.0 was a fictitious entity created by the GRU, Russian military intelligence.