By Manuel Farías
LIMA, May 16 (Reuters) - Peruvian socialist presidential candidate Pedro Castillo and right-wing rival Keiko Fujimori are neck and neck just three weeks before the presidential runoff in the Andean nation, an Ipsos Peru voter simulation suggested on Sunday.
The poll, in which respondents fill out mock voter forms and place them in boxes to preserve their privacy, showed Castillo had 51.1% support, while Fujimori had 48.9%. The gap in the survey published in the newspaper El Comercio was within the 2.8-point margin of error.
Castillo, a newcomer to politics who has caused market jitters by pledging to rewrite Peru's constitution and nationalize mineral resources, was until recently the clear front-runner to win the second round of the presidential election on June 6.
He has since sought to soften his stance to appeal more to the political center, but Fujimori, the daughter of imprisoned former President Alberto Fujimori, has steadily chipped away at his lead. She polls stronger in the cities, while he leads in the country's interior, from where he hails.
Castillo said on Sunday he was unconcerned by the polling, telling a news conference: "I'm worried about the country. I'm worried about the health situation."
Alfredo Torres, executive president of Ipsos Peru, told El Comercio there was still a long way to go in the campaign.
"You can't call a trend at this stage," he said. "What we can say is that there is no longer a favorite. Today there is a virtual tie."
The poll of 1,202 people was conducted on Thursday and Friday. Ipsos also conducted a voter intention survey over the phone, which further indicated the gap between Castillo and Fujimori had narrowed to within a hair's breadth.
Another poll released on Sunday by the Peruvian Studies Institute (IEP) for the newspaper La República showed that Castillo led Fujimori in voting intentions by 36.5% to 29.6%.
That survey was conducted by telephone from Thursday to Saturday, with a margin of error of plus or minus 2.8 points. (Reporting by Manuel Farias; Writing by Aislinn Laing; Editing by Peter Cooney)