South Korean news agency Yonhap quoted a government source as saying that the intelligence chiefs of the US, South Korea, and Japan are expected to meet in the next couple of days in closed talks about North Korea.

The news agency added that Avril Haines, the US Director of National Intelligence, will meet with her South Korean and Japanese counterparts in their first meeting since last May.

Several days ago, North Korean leader Kim Jong-un considered the US the "root cause" of the tensions on the Korean Peninsula.

Kim affirmed that Pyongyang's weapons were only for self-defense against the US hostile policies.

Last week, Pyongyang and Seoul reconnected their cross-border hotline in a sign of restoring ties, Pyongyang's state media reported.

This comes after North Korea recently tested a new hypersonic missile, to join a race led by major military powers to deploy this advanced system of weapons, while the UN Security Council failed to reach an agreement on a joint declaration on this test.