The US Special Counsel Robert Mueller has said charging President Donald Trump with a crime was not an option, in his first comments on the Russia inquiry.
He reiterated that his report did not exonerate the president and that legal guidelines prevent the indictment of a sitting president.
Mr Mueller did not rule out testifying in Congress but said he would not give information that was not in his report.
Reacting to the remarks, Mr Trump said: "The case is closed! Thank you."
As special counsel, Mr Mueller was tasked with investigating Russian interference in the 2016 presidential election.
His 448-page report said it had not established that the Trump campaign criminally conspired with Russia to influence the election.
However, it did detail 10 instances where Mr Trump had possibly attempted to impede the investigation.
What did Mueller say?
His statement largely reaffirmed what was in the report released with redactions last month.
He said if his team had had confidence that Mr Trump "clearly did not commit a crime, we would have said so".
Mr Mueller added that "the Constitution requires a process other than the criminal justice system to formally accuse a sitting president of wrongdoing," in what was seen as a reference to the ability of Congress to start an impeachment process.
The special counsel said he did not believe it was "appropriate to speak further" about the investigation and that he would not provide any information that was not in his team's report.
With Democratic lawmakers seeking to have him testify in Congress, Mr Mueller said: "The report is my testimony."
He also announced the formal closure of the special counsel office and his resignation from the justice department to return to private life.-BBC