Kim Jong-un, the top leader of North Korea has asked for further strengthening of his country's nuclear force, the state media said on Wednesday. According to the Korean Central News Agency (KCNA), Kim "expressed belief that the scientists of the national defence industry and workers of munitions would bolster up the nuclear force in quality and quantity". North Korea's strategic position has been "put on a new high level on the basis of the powerful Juche-based defence industry", Kim noted. Juche, meaning self-reliance, is an ideology for achieving absolute independence in political, economic, military and international affairs. Kim gave the instruction in a speech delivered at the two-day 8th Conference of Munitions Industry which closed on Tuesday, Xinhua news agency reported. He also felicitated the contributors to the newly devised Intercontinental Ballistic Missile, Hwasong-15, that was fired on November 29, and which is capable of striking the entire US mainland according to Pyongyang. Kim's speech came amidst US Secretary of State Rex Tillerson's open invitation to hold nuclear disarmament talks with North Korea "without preconditions", media reports said.