Mr. Ri rejected suggestions that North Korea’s own nuclear and long-range missile activities, for which it has been sanctioned by the United Nations, were provocative. “No country in the world has been living like the D.P.R.K., under serious threats to its existence, sovereignty, survival,” he said, using the initials for the Democratic People’s Republic of Korea, the North’s official name. “That’s why the D.P.R.K. went with the option to go with a nuclear deterrent, to protect our people.”

He accused the United States of using its military power to deliberately subvert any dialogue between North and South Korea — which is also a standard North Korean assertion. But in a variant of that theme, he said the American behavior “is reminding us of the historical lasting symptom of a mentally retarded patient.” Asked later to explain the analogy, Mr. Ri said, “The U.S. has been doing it for over six decades on our doorstep.”

His critique came as more news dribbled out of North Korea over the two detained American tourists, Matthew Todd Miller, 24, and Jeffrey Edward Fowle, 56, suggesting that they are likely to be put on trial soon for unspecified hostile acts. A television news crew for The Associated Press, the first Western news agency with a bureau in the North’s capital, Pyongyang, was permitted by the North Korean authorities to briefly visit with the two under the condition that the location not be disclosed. It was unclear from The A.P.’s account whether the two were interviewed together or separately, or whether they had been coerced. But both were quoted as saying they needed help from the American government and feared they would be incarcerated for long periods.

“The horizon for me is pretty dark,” Mr. Fowle was quoted as saying. Mr. Miller was quoted as saying, “I expect soon I will be going to trial for my crime and be sent to prison.” North Korea has not explained the nature of the accusations against them.

On Thursday, a pro-North Korea newspaper in Japan published an interview with Kenneth Bae, an American missionary who has been incarcerated in North Korea for nearly two years, in which he said that his health was failing and that he had lost faith in the American government’s efforts to win his release.