This photo, carried by North Korea's official Korean Central News Agency, April 14, shows Jang Chang-ha, president of the Academy of National Defense Science, issuing an order to launch the Hwasong-18 intercontinental ballistic missile. Yonhap

A key North Korean official in charge of Pyongyang's missile development has been leading an agency considered to be handling the country's policy of strengthening its nuclear force, South Korea's unification ministry said Thursday.

Jang Chang-ha, president of the Academy of National Defense Science, has been identified as the chief of the Missile General Bureau, as the name tag on his military uniform points to his new title, the ministry said, citing photos carried by the North's state media outlets.

"The missile bureau is presumed to be the agency in charge of North Korea's project to strengthen its nuclear force, given that the flag representing it has a symbol of intercontinental ballistic missiles (ICBMs) and nuclear weapons," a ministry official told reporters.

The existence of the bureau was first known in February, when its flag was detected at an enlarged military meeting in photos carried by the North's state news agency. North Korean observers speculate it was created in April 2016 as an entity overseeing the production and management of North Korea's nuclear weapons and missiles.

Jang, regarded as a key missile official, was promoted to a general last November for his contribution to the development of the Hwasong-17 ICBM.

He is among blacklisted North Korean officials under U.N. sanctions over Pyongyang's nuclear and missile programs. He has also been on the list of unilateral sanctions by South Korea and the United States.

Meanwhile, the unification ministry said it is keeping close tabs on a possible change in the status of Ri Son-gwon, the head of the United Front Department (UFD) tasked with handling inter-Korean relations, at the ruling Workers' Party.

Ri may have been demoted from an alternate member of the party's political bureau, but there seems to be no change in his status as the UFD chief, it added. (Yonhap)