In the latest move to solidify his control over North Korea, leader Kim Jong-un made an appearance at a meeting of the country's security personnel, a South Korean government source said Thursday.

South Korea's unification ministry source said the recent meeting likely held on Wednesday between Kim and members of the Korean People's Army (KPA) security forces seems to have been orchestrated by Pyongyang to bolster Kim's image as the supreme commander and to secure backing from the key "grass root" military organization.

The gathering reported by the regime's Korean Central News Agency earlier in the day is the first to be held in 20 years. KPA security personnel are the North Korean equivalent of the Defense Security Command in South Korea and are responsible for counter espionage operations and internal surveillance.

Kim, thought to be around 30, inherited the communist country upon the sudden death of his father Kim Jong-il in late 2011.

Before taking power, he had very little time to be groomed for the top post, which raised doubts among experts about his ability to take charge. 

"There has been an increase in large public gatherings attended by Kim in the past year that may be part of a plan to exert greater control over every aspect of the country, boost the morale of various state agencies, rally people around the new leader, and propagate the orders of the ruling party to officials and soldiers," said the official, who declined to be identified.

Compared with his father, who rarely made public appearances or gave speeches, the source said the incumbent leader has courted the people he has met and frequently made speeches.

The insider then said that the meetings are not randomly arranged and seem to follow a pattern with the leader placing the most importance on winning over working-level officers and officials in security organizations, the military, the ruling party and the government.

Kim was present at the meeting of company commanders and political commissars of the KPA late last month, as well as the meeting of secretaries of cells of the Workers' Party of Korea (WPK) in January, according to media reports. 

He has also been present in many other official party and government events like the meeting of the Squad for the Three-pronged Revolution, state prosecutors and regional police chiefs. The so-called Three-pronged Revolution, which was first created in 1973, aims to boost the country production and encourage reform across the board.

Representing such goals, Kim said in an open letter that the country is at a critical crossroads and that the security forces must redouble their efforts to safeguard the country.

Reflecting the call by the leader, Col. Gen. Jo Kyong-chol, the head of the security organization, emphasized that all security personnel must guard the leader and the policies of the state in accordance with the rules set by the country's founder, Kim Il-sung, and late leader Kim Jong-il. The founder is the grandfather of the incumbent head.

The unification ministry spokesman, meanwhile, said that while Seoul is checking reports that an American citizen is being detained in the North, he did not think it is appropriate for him to comment on it.

"The U.S. government has been guarded on this matter," he argued.

American media reported Wednesday that Merrill Newman, an 85-year-old from Palo Alto, California, is being held in the North after entering the country on a tourist visa. (Yonhap News)