“North Korea has been engaged in a so-called headline strategy,” Kim Jang-soo said, referring to an almost daily drumbeat of North Korean threats since early March and the news stories they have generated.

North Korea is raising tensions in an effort to frighten and force the United States and South Korea into negotiations and concessions, he said. The pressure was also aimed at China and Russia in an effort to push them to mediate on North Korea’s behalf, he said.

“We see through their motive,” he said. “Although North Korea shows no signs of attempting a full-scale war, it will suffer damage many times more than we do if it launches even a localized provocation.”

South Korea “has no intention of attempting premature dialogue just because of a crisis,” Mr. Kim said, urging the North to ease tensions so talks can start.

In an interview on the ABC News program “This Week” on Sunday,President Obama’s senior adviser,Dan Pfeiffer, declined to discuss what the United States would do if North Korea tested another missile, but said that it would not be a surprise if it did. “We have taken the steps we need to be able to protect our allies, protect the homeland,” Mr. Pfeiffer said. “The real focus and the onus is on North Korea to do the right thing.”

Two senior senators also criticized China on Sunday for not doing more to press North Korea to tone down its confrontational stance. “The Chinese hold a lot of the cards here,” Senator Charles E. Schumer, Democrat of New York, said on the CBS News program “Face the Nation.” “They’re by nature cautious, but they’re carrying it to an extreme. It’s about time they stepped up to the plate and put a little pressure on this North Korean regime.”

Senator John McCain, Republican of Arizona, appeared on the same program and said China could use its economic leverage over North Korea, cutting off support entirely “if they want to.” Mr. McCain said China’s failure to push North Korea was “very disappointing.”