South Korea's unification ministry said Monday it is keeping tabs on North Korea's nuclear and missile activities after Pyongyang hinted last week at lifting its self-imposed moratorium on nuclear and long-range missile tests.

On Wednesday, North Korea held a politburo meeting of its ruling Workers' Party, presided over by leader Kim Jong-un, and decided to consider restarting "all temporally-suspended" activities, citing Washington's "hostile policy" against its regime.

Asked about a news report that said the North appears to be maintaining its Punggye-ri nuclear test site, which it is said to have dismantled in 2018, ministry spokesperson Lee Jong-joo declined to confirm "detailed intelligence matters on North Korea's nuclear facilities" but said the government is monitoring related moves.

"The government is following North Korea's nuclear and missile activities under close South Korea-US coordination," Lee told a regular press briefing.

It is also monitoring the possibility of a notable event in North Korea to mark key national holidays -- the 80th birthday of Kim's late father, Kim Jong-il, on Feb. 16 and the 110th birthday of his late grandfather, Kim Il-sung, on April 15 -- amid signs the North may be preparing a military parade.

Pyongyang tends to commemorate every fifth and 10th anniversary with major events.

"The government is ... preparing for all possibilities in cooperation with relevant agencies and countries," Lee said. "But rather than jumping to conclusions, we will make a comprehensive assessment after looking into North Korea's activities with a sense of concern."

Tensions have ratcheted up on the Korean Peninsula in recent weeks after the North conducted four missile tests -- including two of what it claims to be a hypersonic missile -- since the start of the year. (Yonhap)