South Korea is in talks with the United States to continue close coordination on pending alliance issues following the appointment of Christopher Miller as the US acting defense secretary, Seoul's defense ministry said Thursday.

On Monday, US President Donald Trump fired his defense chief, Mark Esper, just days after his election defeat to former Vice President Joe Biden. Esper was sworn in as secretary of defense in June last year.

"We consider it a natural matter to communicate with the new acting secretary side for close coordination between the defense authorities of South Korea and the US," deputy ministry spokesperson Col. Moon Hong-sik said during a regular press briefing. "The two countries have a shared understanding on that, and as far as I know, (related) discussions are under way."

The ministry earlier said it will continue to work closely with the US under the incoming Biden administration to maintain a firm combined readiness posture.

Setting up a task force led by Vice Defense Minister Park Jae-min, the ministry has been reviewing policy measures to prepare for possible changes in defense issues between the two sides. (Yonhap)