SEOUL, South Korea » North Korea has taken its propaganda war against South Korea and the United States to a new frontier: YouTube and Twitter.

In the last month, North Korea has posted a series of video clips on YouTube brimming with satire and vitriol against leaders in South Korea and the United States.

In one clip, it called Secretary of State Hillary Rodham Clinton a "minister in a skirt" and Secretary of Defense Robert M. Gates a "war manic," while depicting the South Korean defense minister, Kim Tae-young, as a "servile dog" that likes to be patted by "its American master."

Such language used to be standard in North Korea’s Cold War-era propaganda. Its revival is testimony to the increased chill in relations between the two Koreas in recent months.

In the past week, North Korea also began operating a Twitter account called uriminzok, or "our nation."

Both the Twitter and YouTube accounts are owned by a user named "uriminzokkiri." The website www.uriminzokkiri.com is run by the Committee for the Peaceful Reunification of Korea, a main propaganda agency in Pyongyang.

Lee Jong-joo, a spokeswoman for the Unification Ministry in Seoul, said, "It is clear that these accounts carry the same propaganda as the North’s official news media, but we have not been able to find out who operates them."

The two Koreas agreed to stop their psychological war after their first summit in 2000. But South Korea resumed propaganda radio broadcasts, consisting mainly of Western pop songs and outside news — across the border in May when it accused the North of torpedoing one of its warships, killing 46 sailors.

North Korea, which denies involvement, has vowed to retaliate. It appears to have found a way with Twitter and YouTube, whose intended audience is clearly South Koreans. (North Korea keeps its people isolated from the outside world).

"YouTube and Twitter gave North Korea a high-tech detour for its propaganda," said Paik Hak-soon, an analyst at Sjong Institute. "But fundamentally, it’s not new technology but rather political tension that drives the North to lash out desperately in the face of mounting international pressure.

During the Cold War era, South Korea punished people caught listening to North Korean broadcasts. Several years ago, during the brief era of its "Sunshine Policy" of engaging the North, the South allowed its people access to North Korean websites. But today, when a computer user in South Korea clicks on an item on the North Korean Twitter account, a government warning against "illegal content" pops up.

These blocks have triggered criticism here that the Seoul government does not trust its people to form their own opinions about the totalitarian North.

But the government says the North is using the Internet to spread conspiracy theories about who was behind the sinking of the South Korean warship, including one claim that an American submarine did so to foster a militant mood in the South.

The Twitter account, which provides links to the North Korean website, had 928 followers as of Monday. But a few YouTube video clips uploaded by the North commanded thousands of views.

In one such clip, North Korea attacked Yu Myung-hwan, the South Korean foreign minister, who recently criticized "pro-North Korean youths" who voted for the opposition in the June local elections, saying, "If they like the North so much, they should go and live under Kim Jong-il."

The clip’s narrator calls Yu a "pro-American flunky" and advised Yu to earn a living "mopping the floor of the Pentagon."

Another clip — claimed that North Korea would prevail in a war with the "American imperialists" because it was armed with nuclear-fusion technology; its juche, or ideology of "self-reliance"; and a multivolume philosophical treatise written by Kim Il-sung, the North’s founding president and late father of Kim Jong-il, who died in 1994.

"I don’t think this propaganda from the North will have any significant impact among South Koreans," said Yoo Ho-yeol, an expert on North Korea at Korea University here. "People watch this for fun, not to be influenced."

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