Factbox - A scorecard of key players in U.S. special counsel Russia probe

FILE PHOTO: U.S. President Donald Trump's son, Donald Trump Jr. speaks during a campaign event for Republican congressional candidate Rick Saccone at the Blaine Hill Volunteer Fire dept. in Elizabeth Township, Pennsylvania, U.S. March 12, 2018. REUTERS/Brendan McDermid/File Photo

(Reuters) - Special Counsel Robert Mueller and other U.S. prosecutors have been investigating whether President Donald Trump's 2016 campaign conspired with Russia and whether the president unlawfully tried to obstruct the inquiry.

U.S. intelligence agencies have concluded Russia interfered in the presidential election with a campaign of hacking and propaganda to sow discord in the United States and damage the Republican Trump's Democratic opponent, Hillary Clinton. Russia denies it. Trump has denied collusion and obstruction of justice.