The announcement comes days after Ukraine said its forces clashed with North Korean units in the Russian border region of Kursk.

North Korea has ratified a mutual defence treaty with Russia signed by the two countries' leaders in June, which calls for each side to come to the other's aid in case of an armed attack, state media KCNA said on Tuesday.

SEOUL, Nov. 12 (Yonhap) -- 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 ...