Videos on social media purportedly from the campaign event showed people taking cover and screaming as gunfire sounded.

According to opinion polls, Villavicencio's support was at 7.5%, ranking him fifth out of eight presidential candidates for the August 20 vote.

Villavicencio was an outspoken critic of former President Rafael Correa and was sentenced to 18 months in prison for defamation over statements made against the former president.

He fled to Indigenous territory within Ecuador and later was given asylum in Peru.

As a legislator, Villavicencio was criticized by opposition politicians for obstructing an impeachment process this year against Lasso, which lead the latter to call the early elections.

Villavicencio had pledged to combat corruption and reduce tax evasion.