President Donald Trump speaks to the press before boarding Marine One as he departs from the South Lawn of the White House in Washington, March 22, 2019.

Attorney General William Barr said Sunday that special counsel Robert Mueller's Russia investigation did not find sufficient evidence to establish that President Donald Trump committed obstruction of justice, or that the president's campaign coordinated with Moscow's efforts to influence the 2016 election.

In a four-page letter to top lawmakers, the top Justice Department official summarized key findings from Mueller's historic investigation. The probe, which ended as Mueller submitted his final report to Barr on Friday, has dogged the Trump administration and gripped the nation for nearly two years. Barr had the authority to decide what information to share with both Congress and the public, including whether they will see Mueller's full report.

Read the full letter here.

In his letter, Barr breaks down two sections of Mueller's report: Russia's efforts to affect the 2016 election and whether the president obstructed justice. Trump's firing of former FBI Director James Comey and other actions throughout the probe raised concerns about the president trying to end the investigation.

While the president and his allies saw vindication in Barr's letter, Democrats questioned how Barr came to his conclusions and called for more information from Mueller's report. Citing "concerning discrepancies," House Judiciary Committee Chairman Jerry Nadler, D-N.Y., said he planned to call the attorney general to testify.

Nadler testimony tweet

The attorney general says Mueller did not conclude whether Trump obstructed justice. He quotes the special counsel as stating, "while this report does not conclude that the President committed a crime, it also does not exonerate him." Barr concluded that he and Deputy Attorney General Rod Rosenstein "have concluded that the evidence developed during the Special Counsel's investigation is not sufficient to establish that the President committed an obstruction-of-justice offense."

The top Justice Department official also said the probe "did not find that the Trump campaign or anyone associated with it conspired or coordinated" with Russia. Barr quotes Mueller as writing: "[T]he investigation did not establish that members of the Trump Campaign conspired or coordinated with the Russian government in its election interference activities."

The attorney general also said Mueller did not find that the Trump campaign coordinated with Russia's cyberattacks on Democratic and Clinton campaign figures or the efforts to spread information obtained in the hacking incidents, "despite multiple offers from Russian-affiliated individuals to assist the Trump campaign." The president's son, Donald Trump Jr., has admitted that he took a meeting with a Russian lawyer after being offered dirt on former Secretary of State Hillary Clinton, his father's 2016 opponent.