Former UN chief Ban Ki-moon made a surprise announcement on Wednesday, saying that he will not run for South Korea’s presidency.

His decision comes against previous expectations that the international figure will delve in domestic politics and contend in the presidential elections, which are likely to take place later this year if suspended president Park Geun-hye is officially removed.

"I will give up my pure aspiration to achieve a change in politics under my leadership and unify the country," Ban said during an impromptu press conference at the National Assembly.

"I was very frustrated by (some of the political circles') parochial, selfish attitudes, and reached a conclusion that it is meaningless to move forward with them," he added.

Ban returned to his native South Korea last month after a decade of service at the helm of the United Nations. Although he never formally announced his candidacy, Ban had been testing the waters of politics at home, touring the country. He repeatedly noted that “I am ready to give my all to uniting the divided country and making South Korea a first-rate nation” – a statement that had stoked speculation about him joining the race to the presidential “Blue House”.

Ban was leading the polls on possible successors of Park, but his approval ratings slumped as his efforts faltered after continued political attacks and corruption allegations involving his relatives embroiled him.

Last month, US prosecutors charged Ban’s younger brother and nephew with bribery for offering money to a Middle Eastern official through an American middleman. The two men allegedly used state funds to buy their building project with millions of dollars in 2013. 

Shortly after the reports, Ban denied he was aware of the circumstances surrounding the allegations against his relatives.

Park was impeached by the National Assembly in December of last year amid mounting popular calls for her resignation over an influence-peddling scandal. A final decision lies in the hands of a Constitutional Court, which is currently debating whether to uphold the parliament’s decision or overturn it.

A ruling is scheduled for June of this year.

If Park is ousted, elections would be held within a two-month period.

(Story with inputs from Reuters)