Seoul, Sep 3 : A day after the North fired cruise missiles following major joint exercise between South Korea and the US, North Korea has conducted a drill for a "simulated tactical nuclear attack." As per North's official Korean Central News Agency (KCNA), "A firing drill for simulated tactical nuclear attack was conducted at dawn of September 2 to warn the enemies of the actual nuclear war danger." "Two long-range strategic cruise missiles tipped with mock nuclear warheads were fired," Yonhap news agency reported quoting the KCNA. On Saturday, South Korea's Joint Chiefs of Staff said the North fired several cruise missiles toward the Yellow Sea at around 4 a.m. The launch came two days after the allies wrapped up their 11-day Ulchi Freedom Shield exercise which Pyongyang has denounced as a rehearsal for invasion. The North claimed the "nuclear strike mission" was "successfully" conducted, with the missiles flying a distance of 1,500 kilometers for 7,672 to 7,681 seconds, respectively, and detonating at a preset altitude of 150 meters above the target. North Korea again denounced the latest major exercise between the allies, which involved at least one US B-1B strategic bomber and fighter jets, as "more openly" revealing their "military confrontation schemes" against the North. "The nuclear force of the DPRK will bolster up its responsible combat counteraction posture in every way to deter war and preserve peace and stability," the KCNA said, referring to the North by its official name. South Korea's military expressed skepticism over North Korea's claims that it successfully carried out its simulated tactical nuclear strike mission. "An analysis indicated that North Korea's announcement this morning was exaggerated. Not all of them succeeded," a senior official of the Joint Chiefs of Staff told Yonhap News Agency on condition of anonymity. In a separate report, the KCNA said North Korean leader Kim Jong-un inspected the Pukjung Machine Complex, a major shipbuilding manufacturing facility, and a major munitions factory and stressed their roles in bolstering the nation's military capability. "He affirmed that a future plenary meeting of the Central Committee of the WPK (Workers' Party of Korea) would set forth an important line of the modernisation of the complex and the development orientation of the shipbuilding industry of the country," the KCNA said in an English dispatch. While inspecting a munitions factory at an undisclosed location, Kim expressed satisfaction and highlighted the importance of its role in "bolstering up the armed forces," it added. /IANS