He will be sworn in as Peru's president on 28 July, after securing just over 50 per cent of the votes, reported BBC.

Castillo, a 51-year-old former school teacher and a union leader, addressed the nation after the jury announced its verdict.

"We are going to work together and bring this country together," said Castillo, according to news outlet RPP, BBC reported. "We are going to reject anything that goes against democracy."

Peru's current President Francisco Sagasti welcomed the announcement.

"May this be the beginning of a new stage of reconciliation, consensus and unity," he added.

Castillo came to power on the promise of nationalising Peru's lucrative mining and hydrocarbon sectors and creation of a million new jobs in a year, the BBC  reported.

He also proposed to re-introduce death penalty to curb crime.

Castillo defeated Keiko Fujimori last month by just 44,000 votes in her third attempt to the presidency.

Official verdict from election officials was delayed due to a series of legal challenges by Fujimori.

Fujimorí produced legal evidence of election fraud, but electoral observers, including the Organisation of American States, found no irregularities.

Before the announcement of Castillo's victory, Fujimori said she would accept the verdict.

Fujimori is the daughter of former President Alberto Fujimori, who is currently serving a 25-year sentence for crimes including corruption and human rights abuses, stated the BBC report.

Fujimori is also facing corruption and money laundering charges.

The report said her defeat in the election means the prosecutors can now go ahead with the charges against her.