The older half sister of North Korea's leader Kim Jong-un appears to be leading a key organization of the North's military, an expert claimed Monday.

Kim Sol-song is seen as leading the decision-making body of the Supreme Command of the Korean People's Army, Lee Yun-keol, a research fellow at the Sejong Institute, said.

"The decision-making organ was said to have been created under the regime of Kim Jong-il, helping the current leader rule the country," Lee said. "Kim Jong-un is at the top of this body, but in reality, Kim Sol-song is the person in charge."

She was born in 1974 to the late former leader Kim Jong-il and his second wife Kim Yong-suk. She has a different mother than Kim Jong-un, who was born to Ko Yong-hui, a Korean resident in Japan.

Kim Sol-song's public activity has not been known amid conflicting views about her role in North Korea's leadership. Some experts said that she had long been shunned away from power.

Kim Jong-un was recommended as the supreme commander of the KPA on Dec. 30, 2011, about two weeks after the death of his father Kim Jong-il.

"She may be serving as chief vice chairperson of the central committee of the ruling Workers' Party of Korea," Lee claimed, adding that Kim may be the first vice chairperson of the State Affairs Commission.

Lee's claim has not been officially confirmed as the North's state media has not mentioned such a role in its reports.

Currently, the WPK's central committee consists of chairman Kim Jong-un and nine vice chairmen, including Choe Ryong-hae.

The SAC, a state apparatus, was set up in June last year, replacing the National Defense Commission, which played a key role under the Kim Jong-il regime. The organ is led by chairman Kim Jong-un and has three vice chairmen, including top military official Hwang Pyong-so.

Cheong Seong-chang, a senior research fellow at the Sejong Institute, earlier claimed that Kim Sol-song is believed to be exerting huge influence on North Korea's policy-making process.

He said that she may be the one who ordered the killing of Kim Jong-nam, the half brother of Kim Jong-un who died at an airport in Malaysia after two Asian women allegedly smeared the banned chemical weapon VX nerve agent on his face.

Meanwhile, Rep. Ha Tae-keung told a radio program last month that Kim Sol-song may be the next assassination target by the North's leader. 

Lee at the think tank said that North Korea's 216 Institute under the SAC is handling the country's nuclear tests while a think tank under the WPK's central military committee is dealing with works on nuclear weapons' miniaturization and standardization.

"Under the Kim Jong-un regime, the SAC and the party's military committee are handling nuclear weapons and strategic missile developments, respectively," Lee said. (Yonhap)