The government says it is continuously monitoring North Korea's nuclear missile activities under close coordination with the United States.

This comes after the International Atomic Energy Agency(IAEA) recently assessed that the North is believed to have resumed production of plutonium for its nuclear warheads at the Yongbyon nuclear facility.

Unification Ministry spokesperson Lee Jong-joo said on Monday that the allies will continue to make efforts toward achieving complete denuclearization and establishing lasting peace on the Korean Peninsula.

The spokesperson, however, declined to confirm details of the North's resumed activity.

Defense Ministry spokesperson Boo Seung-chan also said the allies' militaries are closely tracking North Korea's nuclear activities.

In a report last Friday, the IAEA said that since early July, there have been indications consistent with the operation of the five-megawatt reactor at Yongbyon, including the discharge of cooling water.