SEOUL (THE KOREA HERALD/ASIA NEWS NETWORK) - North Korean leader Kim Jong Un's 21-year-old nephew has been expressing increasing frustration of his life on the run and has begun to develop a habit of daytime drinking, South Korean media reported on Tuesday (Oct 10).

Mr Kim Han Sol, along with his mother Ri Hye Kyong and his 19-year-old sister Kim Sol Hui, has been on the run from the North Korean regime after his father Kim Jong Nam was killed at a Malaysian airport in February.

Mr Kim Jong Nam, who was the half-brother of the North Korean strongman, was murdered with the banned VX nerve agent in broad daylight while waiting for his flight to Macau.

"According to various sources, Kim Han Sol is under 'iron-like' protection at his mother's house. This keeps him safe, but also makes him frustrated at the same time," TV Chosun, a media outlet in South Korea, said on Monday (Oct 9).

"He has been telling the people around him that he is glad that his family is safe, but the protection programme is suffocating. He has also been consuming alcohol often during the daytime, while saying that he had more freedom working in Macau," it said.

Mr Kim Han Sol and the rest of the family were reportedly residing in Macau at the time of his father's death and had worked as an employee at a nearby hotel there. The family had been living a life of exile from North Korea since 2001.

The trio's current whereabouts are unknown, although the respective governments of the Netherlands, China, the United States, and a fourth unnamed nation had offered help to them, according to the group Cheollima Civil Defence, an organisation keeping the family under Pyongyang's radar. The group is believed to be formed of North Korean dissidents.

The Wall Street Journal reported earlier this month that the North Korean regime may be targeting Mr Kim Han Sol, and that there were "attempts by several parties to interfere" with the family's evacuation from Macau, citing an unnamed Cheollima source.

The source also claimed that Canada was among the nations that refused to assist the family.

Mr Kim Han Sol is believed to be the last surviving male of the "Baekdu" descent, the direct bloodline of North Korean state founder Kim Il Sung and Kim Jong Il, which could make him a potential threat to his uncle Kim Jong Un. North Korea's current leader has been consistently eliminating such threats since he rose to power in 2011.

In an interview with Finnish media in 2012, Mr Kim Han Sol openly criticised the reclusive regime and the government saying that he has always dreamed that one day he would return to his homeland to "make things better".

At the time of the interview, he had been studying at an international school in Bosnia and had undergone an educational experience in France.