Kim Yo-jong, the younger sister of North Korean leader Kim Jong-un, seems to have risen above her leadership title as deputy chief of Pyongyang’s propaganda affairs to Kim Jong-un’s personal messenger, aggressively weighing in on US relations and the inter-Korean agenda.

In her second known official statement, released Sunday, she disclosed that US President Donald Trump had sent Kim Jong-un a letter, saying Washington was ready to expand cooperation with Pyongyang to combat the coronavirus.

“The letter signals exceptional rapport between the two heads of state,” she said, noting it remained to be seen whether US-North Korea relations would live up to the personal ties between Trump and Kim.

Two weeks ago, she leveled diatribes against Cheong Wa Dae for expressing “grave concerns” over the North’s weapons test the previous day. The South’s presidential office, which she described as “mentally challenged” and a “frightened dog,” did not respond.

Observers speculate Kim’s latest appearances all point to her elevated status, which was foreseen. She was seen next to Kim Jong-un when he met with Presidents Moon and Trump at Panmunjom on the inter-Korean border in June a year ago, and again so when Kim met with Chinese President Xi Jinping shortly after.

Alongside Kim Jong-un, she also observed the North’s major weapons tests, including the latest round Saturday, when Pyongyang test-fired short-range ballistic missiles similar to the US surface-to-surface missile ATACMS.

A think tank of Seoul’s National Intelligence Service said Kim Yo-jong will soon take on more responsibility as a key part member. Experts said Kim Jong-un was conveying his frustration with unhappiness with UN sanctions when he let his sister speak on his behalf.

“Kim Jong-un is demanding Washington and Seoul roll out sanctions relief or something commensurate that incentivizes Pyongyang to engage in talks,” said Shin Jong-woo, a senior researcher at the Korea Defense and Security Forum. Kim Yo-jong will make a third appearance if she has to, Shin added.

By Choi Si-young (siyoungchoi@heraldcorp.com)