This year, North Korea's calendars began to mark Nov. 29 as an anniversary for its rocket development. On the day in 2017, North Korean leader Kim Jong-un declared the completion of his country's nuclear forces after firing the new ICBM, the Hwasong-15.

"As of now, there are no unusual (North Korean) activities to additionally mention," Col. Kim Jun-rak, the spokesperson of the South Korean Joint Chiefs of Staff, told a regular press briefing, Yonhap news agency reported.

Lee Jong-joo, spokesperson for Seoul's unification ministry, echoed the view.

"There isn't anything that we can specifically comment on regarding any unusual activities of the North Korean military, including possible preparations for a missile launch," Lee told a press briefing.

Lee also said South Korea has yet to confirm any North Korean activities officially celebrating the newly designated anniversary.

The 2017 ICBM launch marked a culmination of Pyongyang's decadeslong pursuit of long-range nuclear delivery capabilities, though questions persist over whether it has mastered the technology that will allow warheads to withstand extremely high temperatures during reentry into the Earth's atmosphere.