The U.S. has condemned the killing of Democratic Action party leader Luis Manuel Diaz, who was shot at a campaign rally on Wednesday.

U.S. Department of State spokesperson John Kirby released a statement concerning the incident Thursday.

"We call on the Government of Venezuela to protect all political candidates and we call on the National Electoral Council to ensure that this campaign is conducted in a manner to encourage full participation by the people of Venezuela," the statement read. "We further note that campaigns of fear, violence, and intimidation have no place in democracy."

Reuters reports Venezuela's government responded angrily to the U.S. linking the killing to the country's upcoming elections.

"Trying to link a murder between criminal gangs with Venezuela's electoral process shows desperation and bad faith," said Foreign Minister Delcy Rodriguez.

Diaz was a prominent leader of the government opposition Democratic Action party. His death came mere days before the vote for a new National Assembly, which the ruling United Socialist Party of Venezuela (PSUV) is at serious risk of losing for the first time in 16 years.

The national head of Democratic Action, Henry Ramos, placed the blame on the Socialists. He said Diaz had been killed by "armed PSUV gangs," according to BBC News.

President Nicolas Maduro said an investigation indicated the killing was due to a gang dispute, and threatened to bring a lawsuit against Ramos for his comments.

"From Jan. 5 onward, I am going to investigate you all for the multiple crimes you have committed," Ramos retorted, pointing to the starting date of the new National Assembly.

The U.S. was not the only nation to condemn the killing, as the United Nations also urged the Venezuelan government to ensure safety for its political opponents.

Brazil also commented on the incident.

"The Brazilian government hopes the Venezuelan government will act to deter any acts of violence or intimidation that might call into question the credibility of the electoral process and the legitimacy of the voting results," a Foreign Affairs Ministry statement said.