(Bloomberg) -- The candidate who came third in Peru’s presidential election, Rafael Lopez Aliaga, said he won’t back frontrunner Pedro Castillo in the runoff, warning that the leftist union leader would turn the country into a “cruel dictatorship.”

Lopez’s stance could bolster the prospects of Keiko Fujimori and her Popular Force party who will face Castillo in a second round tentatively set for June 6.

In a tweet late Wednesday, Lopez, a conservative businessman, denied rumors that he had spoken to Castillo or planned to meet with his Free Peru party.

“Popular Renovation will not support the party of Mr. Castillo because his governing plan will turn our country into a cruel dictatorship like Venezuela or Cuba,” Lopez wrote.

Castilllo, a former school teacher and union leader, surprised the nation Sunday by winning 19% of the vote in the first round presidential election. Fujimori, the daughter of jailed former strongman Alberto Fujimori who is facing corruption allegations herself, was in second place with 13%.

Lopez came in just behind them with 12% of the vote. If he can maintain the loyalty of his 1.6 million voters, it would make him an influential voice in the run-off. Also in the equation is Hernando de Soto, an economist and former central bank director, who came in fourth -- also with about 12% of the vote.

Read More: Peru Socialist Set to Face Fujimori in Battle of Extremes (1)

Castillo’s Free Peru party is based on the socialist ideals championed by Latin American leftists like Hugo Chavez in Venezuela and Evo Morales in Bolivia. Since winning, the party has toned down some of its harshest rhetoric and tried to reassure international investors. Peru is the world’s second-largest copper producer.

Castillo’s press office didn’t immediately respond to requests for comment. But the founder of Free Peru, Vladimir Cerron, suggested there’s an orchestrated campaign afoot to paint Castillo as an extreme leftist tied to the Shining Path terrorist group.

Why is the press “trying to scare the people?” Cerron wrote on Twitter. “What do we call that? Terrorism by media.”

On Wednesday, Castillo told local media he would begin meeting with rival parties next week to build support for his candidacy.

Read More: Peru Candidate Seeks Bigger Cut From Mining, Not State Control

©2021 Bloomberg L.P.