A candidate in Ecuador's forthcoming presidential election who campaigned against corruption and gangs has been shot dead at a campaign rally.
Fernando Villavicencio, a member of the country's national assembly, was attacked as he left the event in the capital, Quito, on Wednesday.
He is one of the few candidates to allege links between organised crime and government officials in Ecuador.
A criminal gang called Los Lobos (The Wolves) has claimed responsibility.
Los Lobos is the second-largest gang in Ecuador with some 8,000 members, many of whom are behind bars.
The gang has been involved in a number of recent deadly prison fights, in which scores of inmates have been brutally killed.
A break-away faction from the Los Choneros gang, Los Lobos is believed to have links to the Mexico-based Jalisco New Generation Cartel (CJNG), for which it traffics cocaine.
Suspicion for the killing had first fallen on Los Choneros, which had threatened Mr Villavicencio last week, but Los Lobos claimed responsibility in a video in which gang members wearing balaclavas flashed gang signs and waved their weapons.
Ecuador has historically been a relatively safe and stable country in Latin America, but crime has shot up in recent years, fuelled by the growing presence of Colombian and Mexican drug cartels, which have infiltrated local criminal gangs.
The killing comes less than a fortnight before presidential elections, in which the issue of insecurity features as the top concern.
The cartels use Ecuador, which has a good infrastructure and large ports, to smuggle cocaine produced in neighbouring Colombia and Peru to the US and Europe.
They have threatened and targeted anyone who they feel stands in their way.
Fernando Villavicencio, a serving congressman and former journalist, had condemned what he said was the lenient approach to the gangs, saying that were he to come to power, there would be a crackdown.
Mr Villavicencio, who was married and had five children, was one of eight candidates in the first round of the election - although he was not the frontrunner and was polling around the middle of the pack.
He is not the first politician to be assassinated. Last month, the mayor of the city of Manta was shot dead, while in February, a candidate for mayor in the city of Puerto López was killed.
But the shooting of a presidential candidate at a public event in the capital is the most brazen attack so far and shocking testimony to the strength of the gangs.
Witnesses say Mr Villavicencio was attacked as he was leaving a campaign event at about 18:20 (00:20 GMT) local time.
The event was held in Quito's financial district, in a building which had previously housed a school.
A burst of gunfire could be heard as the 59-year-old was getting into a car outside the building where, just moments before, he had been meeting voters.
Mr Villavicencio's uncle, Galo Valencia, described the moment his nephew was killed: "We were just a few metres from the school when we were hit by a hail of about 40 bullets."
Mr Valencia said his nephew had been hit by three bullets in the head.
Carlos Figueroa, another witness, said that "30 seconds after he [Fernando Villavicencio] left through the main door, the shots started".
Video from inside the building shows panicked supporters diving for cover. In the chaos, nine other people were injured, including a candidate for the country's assembly and two police officers, prosecutors said.
The suspect was also shot in an exchange of bullets with security and later died from his injuries, the country's attorney general said on social media. Six people have been detained by police in connection with the assassination after raids in Quito, they added.
A state of emergency has been declared and current President Guillermo Lasso has vowed the "crime will not go unpunished".
Mr Lasso, who will not be on the ballot, said he was "outraged and shocked" by the killing, adding: "Organised crime has come a long way, but the full weight of the law is going to fall on them."
The frontrunner in the polls, Luisa González shared her "solidarity" with Mr Villavicencio's family, adding: "This vile act will not go unpunished."
Former vice-president and fellow candidate Otto Sonnenholzner also sent his "deepest condolences and deep solidarity" to Mr Villavicencio's family. "May God keep him in his glory," he wrote. "Our country has got out of hand."