Ecuador's upcoming presidential election was bloodied by the assassination of a presidential candidate at a campaign rally in the capital city on Wednesday amid an escalation in drug cartel fuelled violence in the South American nation.

Fernando Villavicencio, who was campaigning against gangs, corruption and drug dealers, was shot dead in the capital Quito. A suspect was also killed in the shootout, said Ecuador's president  Guillermo Lasso, assuring that the guilty would be punished.

"Organised crime has come a long way, but the full weight of the law will fall on them,” Lasso said as he declared a state of emergency for 60 days.

He also mobilized the armed forces across the country and announced three days of national mourning, according to the BBC.

According to the British broadcaster, Fernando Villavicencio, a member of the country's national assembly, was attacked as he left the event in the capital, Quito, on Wednesday. Villavicencio was also a former journalist.

He is one of the few candidates to allege links between organised crime and government officials in Ecuador, BBC reported.

The rise in violence owing to the growing drug cartel presence has been an election issue in this year's presidential campaign.

A member of his campaign team told local media the 59-year-old was getting into a car when a man stepped forward and shot him in the head, reported BBC.