Koreas' War of Words Raises Concerns SEOUL - Since early this month, North Korea's state-run news media have featured workers vowing to "tear Lee Myung-bak to pieces" and soldiers hurling daggers and spraying machine-gun bullets at targets bearing the image of "the rabid dog Lee Myung-bak." They even reported a "rumor" that Mr. Lee, the South Korean president, had "dropped dead." "On hearing this rumor, people clapped and danced in the streets," the Rodong Sinmun, North Korea's main ruling party newspaper, reported in a dispatch brimming with invective and glee. North Korea's increasingly spiteful vitriol against Mr. Lee - and South Korea's tit-for-tat verbal jabs at the leadership of the North's young new leader, Kim Jong-un - have raised concerns that the two sides are drifting further apart even as the North has moved to improve ties with the United States, the South's closest ally. By stoking tensions with the South, North Korea usually seeks to increase its leverage in its talks with Washington, which prizes stability on the divided Korean Peninsula. But officials and analysts in the South say that this time, the North may have an even more urgent motive. They say that Pyongyang's bristling rhetoric may be as much a reflection of uncertainty within the new leadership as an expression of hostility toward the South Korean government. "It's mainly for domestic consumption," said Kim Young-soo, a North Korea specialist at Sogang University in Seoul. To bolster internal unity, North Korea needs an external enemy, and it has seized upon the Lee Myung-bak government. Late last month, North Korea struck an agreement with the United States to suspend activities at its main nuclear complex in Yongbyon, north of Pyongyang, including uranium enrichment. North Korean diplomats have since met their U.S. counterparts in Beijing to discuss details of the 240,000 tons of food aid that Washington promised as part of the nuclear deal. Last week, the North's chief nuclear envoy, Ri Yong-ho, attended a forum at a U.S. university. But Mr. Ri refused to meet his South Korean counterpart, Lim Sung-nam, who had also traveled there as an observer. On Monday, the cold shoulder turned into a hot scuffle during a U.N. human rights meeting in Geneva, when North Korean diplomats shoved and shouted at South Korean lawmakers who approached them chanting slogans calling on the North to stop punishing North Korean refugees repatriated from China. For Pyongyang, fighting talk against external enemies is routine. Its guiding "army-first" philosophy is based on the notion that the country is under siege by hostile forces. The leadership cultivates a sense of crisis among its people, with textbooks and ubiquitous slogans instilling children and grown-ups alike with hatred of the Americans and the "puppet" South Korean government. Still, as relations between the two Koreas have deteriorated of in the past few years, both sides seem to be reverting to the Cold War habit of hurling insults - and the volume has risen in recent weeks. Anti-Communist slogans had largely disappeared in the South after the Cold War. But now, in some front-line South Korean military units, slogans reminiscent of the old hostilities have returned, especially since a North Korean artillery attack on a South Korean island in 2010. They include: "Let's drive our bayonets into the heart of the North Korean puppet military" and "The best medicine for a rabid dog is the bludgeon," with the rabid dog standing in for North Korea. Last month, a South Korean newspaper ran a photograph of a poster in a South Korean military barracks that called for the death of the late North Korean leader Kim Jong-il and his son Kim Jong-un, who took over after his father's death in December. Soon North Korea's chest-thumping got louder, calling Mr. Lee "garbage" and other unflattering names. Mr. Kim, the Sogang professor, noted that the poster was a much lesser provocation than an incident last June, when a South Korean Army reserve unit used pictures of the North Korean father and son for target practice. Yet, this time, under the new leader Kim Jong-un, the North's reaction was much shriller. "Kim Jong-un, a leader in transition, needs to demonstrate his authority and make countries around North Korea pay attention to him," he said. What we must guard against is that this brimming animosity, and a potential competition among North Korean military units to prove their loyalty to him, might lead to unexpected clashes with the South. For its part, the South Korean government, which once treated North Korean tirades as unworthy of a response, is now pushing back, though it has so far used somewhat restrained language.