Special counsel Robert Mueller broke his silence on Wednesday, speaking publicly for the first time since delivering his report in March on Russian interference in the 2016 election.

In his remarks, Mueller stressed that he did not wish to testify before Congress, as Democrats are requesting, and sought to explain his controversial decision not to charge President Donald Trump with obstruction of justice.

“If we had confidence that the President did not commit a crime, we would have said so,” Mueller said to a packed room of journalists at the Justice Department.

His comments should only further inflame a partisan split about President Trump’s behavior. Supporters of the president have alleged that the investigation is a “witch hunt,” while critics contend that his behavior was criminal. Mueller’s 22-month probe did not establish that the Trump campaign coordinated or conspired with the Russians during the election. Nor did it deliver a judgment about whether or not the president broke the law by obstructing justice. Mueller said his office determined it would be unconstitutional to charge a sitting president.

“A president cannot be charged with a federal crime while he is in office,” Mueller said, adding, “Charging the president with a crime was …not an option we could consider.”

Mueller went on to say that he hoped his brief, 10-minute remarks would be the last he made about the investigation.

“No one has told me whether I can or should testify or speak further about this matter,” Mueller said. “There has been discussion about an appearance before Congress. Any testimony from this office would not go beyond our report. It contains our findings and analysis and the reasons for the decisions we made. We chose those words carefully and the work speaks for itself. And the report is my testimony. I would not provide information beyond that which is already public in any appearance before Congress.”

The report was initially submitted to Attorney General William Barr on March 22. Barr then wrote a letter to Congress describing the report’s conclusions. He noted that Mueller had opted not to charge the president with obstruction and determined that the evidence developed during the investigation was insufficient to establish that the President committed an obstruction-of-justice offense. On April 18, Barr released a redacted version of the 448-page report.

It later emerged that Mueller took issue with Barr’s summation, writing the attorney general a letter in March in which he said that ”[there] is now public confusion about critical aspects of the results of our investigation.”

For his part, Trump has seized upon the findings to claim they represent a “complete and total exoneration.” Following Mueller’s remarks, the president tweeted, “Nothing changes from the Mueller Report. There was insufficient evidence and therefore, in our Country, a person is innocent. The case is closed! Thank you.”

Mueller may not have found evidence that the president committed a crime, but the investigation he led did result in indictments for 34 individuals. It also led to the convictions of several people in Trump’s orbit, including his former campaign chairman Paul Manafort, his personal attorney Michael Cohen, and the former national security adviser Michael Flynn. It also concluded that the Russian government and Russian agents tried to influence the results of the presidential election in 2016.

“I will close by reiterating the central allegation of our indictments, that there were multiple, systematic efforts to interfere in our election,” Mueller said. “And that allegation deserves the attention of every American.”