South Korea's defense chief vowed Friday to keep watertight defense readiness amid ever-growing nuclear and missile threats from North Korea.

Defense Minister Han Min-koo held a teleconference with top military commanders and told them stay focused on fulfilling their own duties of protecting the country and its people against any provocative acts by the North.

"We should remain firm and highly vigilant against any sort of military threat from the North despite a 'very difficult situation' in the country," Han said. 

He appears to have stressed the military's need to not be distracted by the political scandal involving Choi Soon-sil, a close confidante of President Park Geun-hye.

On Tuesday, a day after local TV network JTBC reported that Choi, a private citizen, informally edited some of Park's speeches and meddled in some state affairs, the president made a public apology after acknowledging her close ties to Choi who has held no government position in the past four decades.

In a televised speech which lasted less than two minutes, Park said Choi helped her on speeches and public relations activities during her presidential campaign in 2012 and even after she took office the following year. 

In the past days, defense officials have said the influence-peddling scandal by the president's close friend is "very discouraging" to the morale of soldiers as Park is the commander-in-chief of South Korea's military forces.

Choi Soon-sil is a daughter of Choi Tae-min, a religious figure who reportedly served as the president's mentor before his death in

1994. Park's five-year single term ends in February 2018.

The presidential office is set to announce a personnel reshuffle in the coming days to tame the mounting uproar across the country. The ruling and opposition parties have asked for the appointment of a special prosecutor to thoroughly investigate the case.  (Yonhap)