PHUKET, Thailand  The United States and North Korea fell into an acrimonious exchange on Thursday, with the North Korean government ridiculing Secretary of State Hillary Rodham Clinton as a “schoolgirl” and a “pensioner,” two days after she compared its leaders to unruly children.

At a meeting of Southeast Asian nations here, the war of words competed for attention with Mrs. Clinton’s campaign to marshal worldwide pressure on the North Koreans to dismantle their nuclear weapons program.

On Thursday, the Foreign Ministry in North Korea issued a statement criticizing remarks Mrs. Clinton made this week to ABC News, in which she said the best response to North Korea’s behavior would be to ignore it, as one would a child clamoring for attention.

“We cannot but regard Mrs. Clinton as a funny lady, as she likes to utter such rhetoric, unaware of the elementary etiquette in the international community,” the North Korean statement said. “Sometimes she looks like a primary schoolgirl and sometimes a pensioner going shopping.”