North Korea has conducted a "strike drill" for multiple launchers, firing tactical guided weapons into the East Sea in a military exercise supervised by leader Kim Jong Un on Saturday, the country's state media reported on Sunday. The purpose of the drill was to test performance of "large-caliber long-range multiple rocket launchers and tactical guided weapons by defence units", the Korean Central News Agency said. Giving orders on Saturday for the test firing, Kim stressed the need to "increase the combat ability so as to defend the political sovereignty and economic self-sustenance" of North Korea in the face of threats and invasions, the report said. Photographs released by KCNA showed the tactical guided weapons fired could be a short-range, ground-to-ground ballistic missiles, according to Kim Dong-yub, a military expert at Korea's Kyungnam University's Institute of Far Eastern Studies. But despite the latest sabre-rattling from Pyongyang, Trump insisted that a breakthrough was possible. "Kim Jong Un fully realises the great economic potential of North Korea, & will do nothing to interfere or end it," Trump tweeted."He also knows that I am with him & does not want to break his promise to me. Deal will happen!"The US leader did not elaborate on Kim's promise. The North Korean drill comes just days before US special representative Stephen Biegun is to visit Japan and South Korea for talks on Pyongyang's nuclear arsenal.