N. Korea vows to turn South's leadership to ashes

However, it is unlikely that North Korea would launch a large-scale military attack against South Korea, which is backed by nearly 30,000 U.S. troops stationed in the South, said Kim Young-soo, a professor at Sogang University in Seoul.

Late Monday, a spokesman for the Foreign Ministry accused the U.S. of slander and of spearheading the campaign of criticism of its rocket launch. The launch prompted the U.S. to halt a Feb. 29 deal to provide Pyongyang with much-needed food aid in exchange for a moratorium on nuclear and missile activity.

In Washington, State Department spokeswoman Victoria Nuland said North Korea "needs to understand that it's not going to achieve anything but further isolation and pressure by threats, by launches, by any of this."

Associated Press writers Youkyung Lee and Jiyoung Won in Seoul, South Korea, contributed to this report.