North Korean leader Kim Jong-un has signed off a defense pact with Russia, the North's state media reported Tuesday, as Pyongyang sent its troops to Russia in support of Moscow's invasion of Ukraine.

The treaty on "comprehensive strategic partnership" between North Korea and Russia was ratified the previous day as a decree from the North Korean leader, the North's Korean Central News Agency reported.

The report noted that the treaty will take effect from the day both sides exchanged ratification instruments.

Kim and Russian President Vladimir Putin signed the treaty in Pyongyang in June, which includes a provision committing both nations to mutual military assistance in the event of an attack on either side.

Russia's news agency TASS has reported that Putin signed the pact on Saturday.

Since the treaty was forged in June, North Korea and Russia have elevated their military partnership to new heights.

The United States has confirmed that as many as 10,000 North Korean troops have been sent to Russia's western front-line Kursk region with the possibility of engaging in combat against Ukrainian forces.

The recent finalization of the mutual defense treaty by both North Korea and Russia raises speculation that North Korean troops might soon begin combat engagement in earnest.

An official at South Korea's unification ministry noted the possibility of the two countries holding a ceremony to exchange ratification instruments, involving high-level officials.

In a recent TASS report, Putin mentioned the possibility of the two countries holding joint military exercises, suggesting a further deepening of their military cooperation. (Yonhap)