WASHINGTON, D.C.: Special counsel Robert Mueller on Friday submitted his long-awaited report into an explosive two-year investigation of Russian meddling in Donald Trump's 2016 election -- a probe the president denounces as a 'witch hunt' and opponents say could fuel impeachment.

What the report says is confidential, but Attorney General Bill Barr wrote in a letter to Congress that he might be able to summarize its 'principal conclusions' for Congress as early as this weekend.