Kamala Harris has gained ground recently due to her debate performance, particularly her exchange over race with Joe Biden.
Candidates will deliver speeches to a mass audience on Saturday and Sunday and attended smaller meet-and-greets.
MPs from the African National Congress, which won 230 out of 400 seats on May 8, choose the head of state in the parliament's first post-election sitting.
The protestors were the supporters of the defeated presidential candidate Prabowo Subianto, who has said he will challenge the election results in the Constitutional Court for electoral fraud.
Exit polls showed Widodoas much as 11 percentage points ahead of his firebrand ex-general rival Subianto.
Barr said Mueller found no evidence that Trump's 2016 campaign team conspired to collude with Moscow to influence the election.
The report by Mueller, a former FBI director, is a nearly two-year investigation into the allegations of Russian interference in the 2016 US presidential elections.
In reality, legal experts say, Mueller may have dug up compromising material about Trump's Russia links, but not enough to stand up in a court of law.
The announcement was widely expected after the 52-year-old champion of women's rights told TV host Stephen Colbert in January she would be forming an exploratory committee.
The question now for Sanders is whether he can stand out in a crowded field of Democratic presidential candidates who also embrace many of his policy ideas and are newer to the national political stag
Winning a presidential caucus can launch a candidate's career into the stratosphere, while finishing back in the pack often prompts an inglorious exit.
Trump's former aide indicted in Mueller probe, held; White House says nothing to do with US President
The former Trump campaign adviser was later released on bail by a Florida court after posting a USD 250,000 bond after he was produced in the court.
In the 24 hours after Harris made the announcement on ABC's "Good Morning America", 38,000 donors gave USD 1.5 million to her campaign, the Fox News reported.
Parliamentary elections were fraught with delays after the few staff trained on the biometric system did not show up at the polling booths and countless registered voters could not find their names on
Specifically, political micro-targeting was particularly effective when based on ideology, gender or educational level, much less so when based on race or age.