North Korea’s ruling party has promoted Kim Jong Un’s younger sister, Kim Yo Jong, to a senior post, highlighting her growing influence in the secretive regime, state media said Tuesday.

Thousands of party elites have packed the capital Pyongyang for a once-in-five-years summit of the ruling Workers’ Party, a gathering that directs state efforts on everything from diplomacy to war planning.

Kim Yo Jong — long considered one of her brother’s closest lieutenants — was promoted to department director within the party’s apex central committee, the Korean Central News Agency said.

Although it was not clear which department she would lead, she has previously held a senior role within the party’s propaganda unit.

Kim Yo Jong has in recent years emerged as one of the most powerful figures in North Korea, playing a highly visible role in diplomacy, nuclear negotiations and other matters of state.

“Kim Yo Jong is one of the very few people Kim Jong Un can trust and rely on,” said Ahn Chan-il, a researcher originally from North Korea.

“She also served as a working-level official for Kim’s summits with Trump in Singapore and Hanoi. She is experienced and seasoned,” he told AFP.