“I’m stepping forward with a determination to change the government,” Mr Yoon said. “I’ll join forces with everyone yearning for a shift in power and achieve that surely.”
Mr Yoon, who once led Mr Moon’s push against corruption, resigned from the top prosecutorial post in March after a dispute over his administration’s plans to bring reforms in the prosecution system. He criticised the plans as a drive to limit prosecutors’ authority and destroying the nation’s constitutional values.
Their ties deteriorated when the president’s political allies were investigated over corruption and other charges.
The former chief prosecutor is known for cracking down on corruption among corporate businessmen and politicians. His investigations against Samsung Electronics vice chairman Lee Jae-yong led to his arrest in 2017 over allegations of bribery and embezzlement.
According to a survey, he was a top pick as a top conservative candidate to become the country’s next leader with 32 per cent of respondents in his favour in a poll by Korea Society Opinion Institute, according to Nikkei Asia.
Mr Yoon has not yet announced to join any political party but it is widely believed that he would join the main opposition People Power Party for the presidential election.
He said in the press conference that he agrees with the ideology of the People Power Party but he is yet to decide which political party to join, reported The Korea Herald.
The former prosecutor said he will focus on improving existing socioeconomic policies and vowed to ensure fairness and protect democracy while ushering an era of technological advancement.
“I have no experience in politics but have spent 26 years as a public official with a determination to work only for the people,” Mr Yoon said.
“I dare to tell the people that I am ready to devote everything and dedicate myself for the people and the future of this nation. I promise to do this in the right way, jointly with everyone who desires to overturn the ruling force.”
If elected, he said he would seek to resolve issues and deteriorating ties with Japan with a “grand bargain.”
"Since the normalization of diplomatic relations, ties have deteriorated to the point where it is impossible to recover," Mr Yoon said.
"We should approach [Japan] with a grand bargain that puts all the related issues such as comfort women, forced labor, security cooperation and trade on the table."
When asked about his take on North Korean leader Kim Jong Un, Mr Yoon said: "We don’t need to have an ambiguous illusion nor an ambiguous negative idea on a country’s leader. We should judge him based on how he leads a country."
Mr Moon’s Democratic party dismissed the criticism while hitting back at him for failing to put forth a clear plan of his presidency, calling it “vuague.”
“Today’s announcement of his election bid is full of vagueness and self-contradiction,” party spokesperson Lee So-young said. “He only focused on criticizing the government that he himself served in, and the nature and contents of liberal democracy that Yoon Suk Yeol talked about were vague.”