SEOUL-- North Korea's new calendars for next year have not marked its 2017 launch date of a new intercontinental ballistic missile (ICBM) as an anniversary unlike this year's, a unification ministry official said Tuesday.

South Korea has been monitoring North Korea's activities after its 2021 calendars marked Nov. 29 as an anniversary for rocket development for the first time. On the day in 2017, the North's leader Kim Jong-un declared the completion of his country's nuclear forces after firing a new ICBM, the Hwasong-15.

The North's newly published calendars for next year, however, do not mark the day as such an anniversary, an official at Seoul's unification ministry said.

"We have checked next year's calendars and found no marking on the day," the official told reporters on background. "We will continue monitoring to see if there are any other related moves."

Even after publishing 2021 calendars with the rocket development anniversary marked, the North has stayed silent on the designation of the new anniversary.

Seoul officials said Monday they detected no unusual North Korean military activities despite speculation Pyongyang could mark the day with a major celebratory event or show of force.

Source: Yonhap News Agency