Incumbent President Daniel Noboa claimed a runaway victory in Ecuador's presidential election on Sunday, after voters endorsed the young leader's "iron fist" approach to rampant cartel violence.

With over 90 percent of the votes counted, the National Election Council said Noboa had an unassailable 12-point lead over his leftist rival Luisa Gonzalez.

Official results showed that Noboa had 56 percent of the vote, against Gonzalez's 44 percent, which was a far bigger winning margin than expected after a virtual tie in the first round.

Speaking to jubilant supporters in his hometown of Olon, the 37-year-old president claimed a "historic victory".

"A huge hug to all those Ecuadorians who always believed in this young president!" he said. "Ecuadorians have spoken, from tomorrow morning we will go to work."

Gonzalez — seemingly shocked by her weak showing and perhaps the end of her dream of becoming Ecuador's first woman president — immediately questioned the results.

She accused Noboa of "the most grotesque electoral fraud" and called for a recount of the ballots.

"I refuse to believe that the people prefer lies over the truth," she said.

She did not immediately provide evidence for her claims of fraud.

'Ecuador is divided’

Noboa, the guitar-strumming son of a billionaire banana magnate, has staked his political fortunes on tough security policies designed to snuff out the gangs.

He has deployed the military to the streets, captured drug capos and invited the United States to send special forces.

On the eve of the ballot, Noboa declared a 60-day state of emergency in the capital Quito and several provinces, underscoring the tense state of affairs.

The once-peaceful nation averaged a killing every hour at the start of the year, as cartels vied for control over cocaine routes that pass through Ecuador's ports.

Rampant bloodshed has spooked investors and tourists alike, fueling economic malaise and swelling the ranks of Ecuador's poor to 28 percent of the population.

In the volcano-ringed capital, voters wrapped up against the Andean chill and flocked to the polling stations.

"I think Ecuador is divided, but I think we all understand we're in a situation where we have to unite, whoever is leading the government," said 21-year-old architecture student Camila Medina.

In total, about 13.7 million Ecuadorans were obliged to vote.