The US special counsel Robert Mueller has submitted his report on alleged interference in the 2016 presidential election.
The former FBI director was appointed by the Justice Department in 2017 to investigate the allegations.
He has now submitted the report to attorney general William Barr.
In a letter to members of Congress, Mr Barr wrote: "Special Counsel Robert S Mueller III has concluded his investigation of Russian interference in the 2016 election and related matters.
"I am reviewing the report and anticipate that I may be in a position to advise you of the Special Counsel's principal conclusions as soon as this weekend."
Details of what are contained in the report have yet to be revealed.
Justice officials in the US are not obliged to publicly - in other words, via Congress - release the report.
However, there will be intense public and political pressure for as much of the document as possible to be made public.
Part of the investigation has focused on whether anybody tied to the Trump campaign cooperated or 'colluded' with Russia.
While it remains unclear what, if anything, Mr Mueller's team has found on that front, several former Trump aides have been indicted or convicted for crimes - such as lying to Congress - as a result of the probe.
President Trump himself has frequently slammed the investigation as a 'witch hunt'.
Earlier this week, however, he indicated that he 'doesn't mind' if the final report is made public.
Mueller has kept a low-profile over the past two years, rarely releasing statements.
Details of the investigation have mostly been revealed via court documents or leaks to the media.
However, in an unusual move, the special counsel's office broke their silence in January to publicly dispute the accuracy of a report claiming President Trump directed his former lawyer to lie to Congress.
