THE left candidate for mayor of a violence-plagued Mexican city has been killed just as she began campaigning.

Two sources in the north-central state of Guanajuato said that Bertha Gaytan had been shot dead on Monday on a street in a town just outside the city of Celaya. 

Video footage of the scene posted on social media showed a small procession of people shouting “Morena!” — the name of Ms Gaytan’s party. At that moment, several shots are heard and people are seen running and falling down.

It was the latest killing in the increasingly bloody run-up to Mexico’s June 2 elections. At least 14 candidates have died violently since the start of this year. 

Morena is also the party of President Andres Manuel Lopez Obrador, who is due to leave office in September. 

The June 2 elections will decide his successor, as well as many state and municipal posts.

Guanajuato has for some time had the highest number of murders of any state in Mexico and Celaya is arguably the most dangerous place, per capita, to be a police officer in North America. 

At least 34 police have been killed in Celaya in the last three years.

Last weekend, the mayor of Churumuco, a town in neighbouring Michoacan, was shot dead at a taco restaurant in the state capital Morelia.