North Korean leader Kim Jong-un is expected to stand alongside his Chinese and Russian counterparts, Xi Jinping and Vladimir Putin, at a high-profile military parade in China this week, Seoul's spy agency said Tuesday.

Axar.az informs, citing Yonhap, Kim is set to arrive in Beijing on Tuesday afternoon after having crossed the border between the two countries at dawn, the National Intelligence Service told lawmakers at a closed-door briefing.

He was possibly accompanied by his wife, Ri Sol-ju, and sister, Kim Yo-jong, on the trip, it added.

The NIS also said North Korea is likely to additionally send some 6,000 soldiers to Russia in its third batch of troop deployment to aid Moscow's war with Ukraine, noting that around 2,000 North Korean troops are estimated to have been killed so far during combat.

Since October last year, North Korea has sent around 13,000 troops and conventional weapons to support Russia's war efforts.