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 maniac,” 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 Koreas in recent months.