Former US special counsel Mueller says he did not exonerate Donald Trump

Former US special counsel Robert Mueller made a long-awaited congressional appearance Wednesday to testify about his investigation into Russian interference in the 2016 election and President Donald Trump's conduct during the probe.

Mueller set out by reiterating what his probe had established: that Russia interfered in the 2016 election "in sweeping and systematic fashion."

And he restated that "the investigation did not establish that members of the Trump campaign conspired with the Russian government in its election interference activities."

Crucially, he reaffirmed that his team had not investigated "collusion," which is not a legal term -- giving the lie to Trump's persistent claims the report established "no collusion."

Mueller also repeated that Justice Department policy meant he could not make a determination as to whether the president committed a crime in his in efforts to tamper with the investigation.

"That was our decision then and it remains our decision today," Mueller said.

But he gave the Democrats a key victory -- and a rare quotable line -- when he said "the president was not exculpated for the acts he allegedly committed."