Mexico City, June 3 (teleSUR-RHC)-- An eightth candidate in the midterm Mexican elections that will take place this coming Sunday has been shot and killed. Miguel Angel Luna was running for the federal chamber of deputies or Lower House of Congress' 32nd district in Chalco, State of Mexico, but was murdered Tuesday at his campaign office, local police reported.

The Democratic Revolution Party (PRD) candidate to the lower house of Congress was attacked by at least three unidentified men who entered his office and shot him various times, after which he was rushed to a local hospital where he died, according to preliminary police reports.

The death of Luna comes a day after thousands marched in Mexico City to demand increased security measures ahead of the elections, while in Oaxaca and other states various sectors of society have threatened to boycott the elections.

Tonatiuh Gutierrez, a PRD councilperson candidate for Chalco, some 30 miles east of Mexico City, was also injured during the attack, according to party officials.

“We condemn the attack against Miguel Angel Luna and we demand that the crime be solved as soon as possible,” the PRD said in statement. The party also demanded authorities to guarantee the safety of all candidates and the population ahead of the June 7th elections, in which 500 lower house lawmakers will be voted, as well as nine governors in as many states across Mexico.

In total, 1,993 posts are up for grabs and about 83 million Mexicans are registered to vote this weekend.

The national leader of the Worker's Party (PT), Alberto Anaya Gutierrez, reminded local press that he had warned a few days ago of the possibility of violence taking place in order to instill fear among the voting population. He said there are unidentified groups interested in boycotting the elections through fear and intimidation, in light of which, he called on authorities to implement a security plan to guarantee the safety at polling stations this Sunday.

According to Mexican news outlets Sinembargo and El Universal, 42 electoral candidates across the country have been attacked, of which seven have been killed, including at least three mayoral hopefuls.

Increasing electoral violence in Mexico is posing an enormous challenge for federal authorities, who are facing the worse pre-election atmosphere in history, according to various political analysts.