SEOUL • After successful missile launches, North Korean leader Kim Jong Un often exchanges smiles and hugs with the same three men and shares a celebratory smoke with them.

The three, shown with Mr Kim in photographs and TV footage in North Korean media, are of great interest to security and intelligence agencies since they are the top people in the secretive country's rapidly accelerating missile programme, South Korean officials said.

They include Mr Ri Pyong Chol, a former top air force general; Mr Kim Jong Sik, a veteran rocket scientist; and Mr Jang Chang Ha, the head of a weapons development and procurement centre.

The three have been individually identified previously but the photographs and TV footage show they are clearly Mr Kim's favourites.

Their behaviour with him is sharply at variance with the obsequiousness of other senior aides, most of whom bow and hold their hands over their mouths when speaking to the young leader.

Unlike most other officials, two of them have flown with Mr Kim in his private plane Goshawk-1, named after North Korea's national bird, state TV has shown.

With their ruling Workers' Party, military and scientific credentials, the trio are indispensable to North Korea's rapidly developing weapons programmes - the isolated nation has conducted two nuclear tests and dozens of missile launches since the beginning of last year, all in violation of United Nations resolutions.

"Rather than going through bureaucrats, Kim Jong Un is keeping these technocrats right by his side, so that he can contact them directly and urge them to move fast. It reflects his urgency about missile development," said Dr An Chan Il, a former North Korean military officer who has defected to the South and runs a think-tank in Seoul.

The most prominent of the three is Mr Ri, according to leadership experts.

Always shown smiling in photographs, he is now deputy director of the Workers' Party Munitions Industry Department, which oversees the development of North Korea's ballistic missile programme, according to the South Korean government and US Treasury.

The department was blacklisted by the US Treasury in 2010 and Mr Ri was named by the South Korean government last year for activities related to the country's weapons programmes.

"He's been around since before Kim Jong Un was even talked about with any seriousness," said Mr Michael Madden, an expert on the North Korean leadership.

The rocket scientist in the trio is Mr Kim Jong Sik.

He started his career as a civilian aeronautics technician, but now wears the uniform of a military general at the Munitions Industry Department, according to experts and the South Korean government.

But it was his role in North Korea's first successful launch of a rocket in 2012 which really helped him earn recognition, Mr Madden said.

Of the three men, the least known about is Mr Jang, president of the Academy of National Defence Science, previously called the Second Academy of Natural Sciences.

The body is in charge of the secretive country's research and development of its advanced weapons systems, "including missiles and probably nuclear weapons", the US Treasury said in 2010 in its decision to blacklist the group.

Mr Jang was added to the Treasury blacklist in December 2016.

"These are the men bringing North Korea's missile programme into the 21st century," said Mr Madden.

REUTERS