SEOUL, March 8 (Yonhap) -- Seoul's defense ministry on Friday dismissed North Korea's warning of a pre-emptive nuclear strike against South Korea and the United States, warning such provocation will only lead to collapse of the communist regime.
Pyongyang has ramped up tensions on the Korean Peninsula with daily threats of attacks in response to new sanctions adopted by the U.N. Security Council over last month's atomic test.
"If North Korea attacks South Korea with a nuclear weapon, Kim Jong-un's regime will perish from the earth," ministry spokesman Kim Min-seok said in a briefing.
"Although atomic bombs were used twice in the past to end World War II, if (the North's) nuclear bomb attacks a free and democratic society, such as the Republic of Korea, mankind would not forgive it," Kim said, referring to South Korea's official name.
North Korea's military has carried out military drills with an unprecedented intensity, mobilizing submarines, fighter jets and special forces, Kim said, noting South Korean and U.S. troops are closely monitoring its latest movement to detect signs of any provocation.
According to a military source, North Korea's artillery unit on the western front has dramatically increased mock fire drills targeting Seoul and its surrounding area since an Army commander inspected the unit earlier this year.
"We are closely monitoring the possibility of artillery attacks near the maritime border," the source said, asking for anonymity as he is not allowed to give out military information.
Three or four submersible vessels are operating near the western maritime border, the so-called Northern Limit Line, and brisk movement is observed on its side, the source said.
Shortly after the U.N. slapped tougher sanctions on the recalcitrant communist state, the North's state media early Friday reported leader Kim Jong-un visited an artillery unit that shelled South Korea's Yeonpyeong Island in November 2010. During the visit, he called on troops to be ready for an all-out war in case of any provocation, the state media said in a separate report.
The annual joint exercise called Foal Eagle began on March and 1 and continues until April 30, involving more than 10,000 U.S. troops along with 200,000 South Korean personnel.
Separately, the joint forces conducted three days of rehearsals from Wednesday to prepare for a computer-simulated drill, called Key Resolve, which will be held from March 11-21, the Combined Forces Command (CFC) said.
"These rehearsals support the ROK-U.S. Alliance's commitment to provide an enduring and capable defense of the Republic of Korea," Gen. James Thurman, the CFC commander, said in a release. "They also allow the ROK and U.S. leadership to understand their training scenarios and identify our key tasks allowing us to continuously adapt and respond to any crisis or contingency our forces may face."