WASHINGTON — The identity of the next leader of North Korea and the security of his hold on power are emerging as topics of intense speculation in defense ministries and intelligence headquarters around the world after reports suggesting that the Hermit Kingdom’s leader, Kim Jong Il, has suffered a stroke.

American intelligence reports to senior government officials surfaced in late August speculating that Mr. Kim may have suffered a stroke as early as August 14, the date of the last public event at which Mr. Kim was seen. The South Korean press reported August 22 that a South Korean diplomat witnessed Mr. Kim collapsing. The South Korean press has also reported that a team of five doctors from China was dispatched last month to Mr. Kim’s residence in Pyongyang.

Suspicions regarding the health of North Korea’s “dear leader” were heightened yesterday when Mr. Kim failed to make an appearance at the 60th-anniversary celebration of the founding of North Korea. The North Korean leader had attended both the 50th-anniversary and the 55th-anniversary celebrations.

One American diplomat told The New York Sun that Secretary of State Rice dispatched Ambassador Chris Hill to Beijing last week to query the Chinese government on the health of Mr. Kim, even though Mr. Hill publicly said the purpose of his visit was to discuss negotiations with North Korea over the decommissioning of its nuclear program. One American intelligence official said yesterday that another intelligence service had passed on intelligence that suggested Mr. Kim had suffered from a stroke.

A former national intelligence officer for East Asia who is a senior fellow at the Brookings Institution, Richard Bush, said the West’s intelligence on North Korea had been notoriously “terrible,” but nonetheless he said some patterns can emerge from what is perhaps the most repressive regime left on the planet.

“This is a regime that understands the value of information security,” Mr. Bush said. “This is also a regime that has observable patterns of behavior from which one can infer certain things. Kim Jong Il appeared in public based on the North Korean media 11 times in June; 16 times in July, and 13 times between August 1 and August 14. He has not been reported to appear in public since then.”

Mr. Bush said that most analysts of North Korea predict that Mr. Kim’s successor will be his second son, Kim Jong-Chul, who is now 27 years old. But Mr. Bush said no public grooming of the younger Kim has taken place to prepare him for the reins of power, a contrast with the steps Kim Il Sung took with his son, Kim Jong Il, in the early 1990s, giving him authority over important party functions before the founder of modern North Korea died.

Whoever likely succeeds Mr. Kim, if he is indeed close to death, will have to bend to the whims of the military, the most powerful institution in North Korea. “As far as who or what will succeed the current situation, we don’t really know,” Mr. Bush said. “Whatever person is put up, the military is going to be the dominant institution. It is not a solid regime, it has a brittleness to it.”

Mr. Bush’s former ambassador to the United Nations, John Bolton, yesterday said he doubted very much that the next leader of North Korea would be one of Mr. Kim’s sons. “So far this is the world’s only hereditary communist dictatorship. The odds of one of the sons inheriting the country are remote. I think the military is the real source of power. Without a clear line of succession the possibility of a power struggle is very real,” Mr. Bolton said.

The former ambassador said for now it was important for America and her allies to put the nuclear negotiations with North Korea on hold and to put off plans to take North Korea off the list of state sponsors of terrorism. “In terms of the six-party talks, any further developments should be on hold until we know who we are talking to,” Mr. Bolton said.

At the State Department, a spokesman, Sean McCormack, declined to comment on any reports regarding Mr. Kim’s health. He did say that America had not seen progress on establishing a verification regime for North Korea’s denuclearization efforts. “We don’t necessarily have a good picture into the decision-making processes of the North Korean regime, but we can see very clearly outputs or lack of outputs,” Mr. McCormack said. “Over the past several weeks, we have not seen outputs in terms of their agreement to a verification regime.”