A regional opposition party leader in Venezuela was shot dead on Wednesday by attackers during a public meeting in the town of Altagracia de Orituco, located in the state of Guarico.

Luis Manuel Diaz, a leader of Democratic Action party in Guarico, was killed at a campaign rally less than two weeks before parliamentary elections were set to take place.

Opposition leaders blame the politician’s death on pro-Maduro militia groups who support the current governing United Socialist Party of Venezuela (PSUV). Venezuelan President Nicolas Maduro, a member of the party, has not yet made a comment regarding Ruiz’s death.

According to The Associated Press, Carolos Prosperi, the leader of Democratic Action party, said that he heard shots fired as the political rally was coming to its end. Other political figures took to social media to say Ruiz was shot in head by someone in a moving car.

Lilian Tintori, the spouse of jailed opposition leader Leopoldo Lopez, was at the event as well.

Top opposition party official Henry Ramos Allup, who was also present, confirmed Ruiz was shot at by armed PSUV members from a vehicle.

Tintori, the 37-year-old media personality-turned-human rights activist, took to Twitter to denounce the attack as well as the atmosphere of "terror" and "harassment" coming from the current Venezuelan regime. She called for the Inter-American Commission on Human Rights to investigate the shooting.

The right-leaning opposition party in Venezuela has asserted that several activists have been wounded in recent days as pro-Socialist Party supporters have interrupted their recent campaign rallies.

Various opposition parties, including the umbrella opposition coalition Unidad Venezuela, denounced the murder.

Election monitors sent to Venezuela by the regional bloc Unasur have condemned the killing and demanded Venezuelan authorities conduct a thorough investigation into Ruiz's murder.

According to Infobae, some witnesses at the tragic event said that, before the shooting, the rally went along without any major problems and the sound of gunshots sparked confusion in the crowd.

The PSUV has the majority of seats in parliament, but recent polls suggest the upcoming election could be an upset for the governing socialist party.