SEOUL, South Korea -- There was no sign of Kim Jong Il at a closely watched parade Tuesday marking the 60th anniversary of North Korea's founding, and Western officials said the all powerful leader - who has not appeared publicly for a month - may be gravely ill.
North Korea's state media was silent about his absence from the parade, a relatively low-key ceremony that unexpectedly lacked much of North Korea's trademark military display, though still took on a decidedly martial flavor.
In a broadcast monitored in Seoul, Korean Central Television showed North Korea's No. 2 leader and other officials and military officers atop a viewing stand. Kim Jong Il was not shown.
In Washington, a Western intelligence official said that it was possible the 66-year-old, known to his people as the "Dear Leader," was gravely ill after he failed to show up at the celebration.
"There is reason to believe Kim Jong Il has suffered a serious health setback, possibly a stroke," the official said, speaking on condition of anonymity to describe sensitive intelligence gathering.
Another official said rumors and reports of a possible illness were based in part on intelligence gathered by other nations.
A senior U.S. official said rumors had been circulating for weeks about Kim's health and his control over North Korea's highly centralized government. That official, who spoke on condition of anonymity about the administration's internal assessment of the situation, said the United States has no independent confirmation that Kim is ill.
Japan's Kyodo news agency reported that Kim did not attend and North Korea's state news agency has made no mention of Kim appearing in public Tuesday.
Kim's last appearance reported by North Korean media came on Aug. 14. South Korean media have reported in recent days that he may be ill and receiving medical treatment, citing government officials.
The South Korean government says it has been unable to confirm them.
White House press secretary Dana Perino said Tuesday that the Bush administration was watching the situation. She called North Korea an "opaque society."
It is not the first time Kim's public appearances have gone unreported for weeks at a time. For example, in the summer of 2006, a period of about six weeks went by between such reports.
Kim's health has been a focus of intense interest because his fate is believed to be closely tied to that of the secretive totalitarian state that he inherited in 1994 from his father in communism's first hereditary transfer of power.
Kim Jong Il took over the communist country after Kim Il Sung died of heart failure - a death that was not announced for 34 hours. He has three sons with two different mothers but has not anointed any of them as his successor.
A spokesman for South Korea's main spy agency, the National Intelligence Service, said it could not immediately confirm Kim's absence. The rally involved about 1 million people, the spokesman said, on condition of anonymity, citing office policy.
The centerpiece of the celebration had been expected to be a massive military parade through Pyongyang's central Kim Il Sung Square - named after the communist country's founding figure - as normally happens in key anniversary years.
The footage broadcast on North Korean television showed what it described as civilian militia goose-stepping in uniforms through the square, adorned with a huge portrait of Kim Il Sung. Some military vehicles, which appeared to carry multiple rocket launchers, could be seen, though there appeared to be no heavy weaponry, such as tanks or missiles.
South Korea's Yonhap news agency reported Monday that the military parade was expected to be the country's largest ever. Though it appeared to have been less than that, martial language was employed.
A man identified by Yonhap news agency as Kim Yong Chun, North Korea's army chief of staff, said in a speech that the country will "continue to bolster its war deterrent" if the U.S. and its followers do not give up what he described as their hostile policies against North Korea.
Kim also said if a war breaks out on the Korean peninsula again, the North's army will "mercilessly" defeat enemy forces, using rhetoric commonly employed by North Korean officials.
Kim attended the parade on the 50th and 55th anniversaries.
South Korean media have speculated that Kim's health has worsened. South Korea's intelligence service has previously said Kim has chronic heart disease and diabetes - denied by Kim himself.
South Korea's Chosun Ilbo newspaper reported Tuesday that Kim collapsed on Aug. 22, citing an unnamed South Korean diplomat in Beijing. The diplomat got the information from a Chinese source, the paper said.
A Japanese scholar and expert on North Korea, Toshimitsu Shigemura, a professor at Tokyo's Waseda University, has even claimed recently that Kim actually died in 2003 and that the North has been using body doubles of Kim for public events.
Chinese Foreign Ministry spokeswoman Jiang Yu said at a regular news briefing Tuesday that she had no information about Kim's health and had not heard that he was ill. She did not answer a question asking when the last time was that Chinese officials spoke directly with Kim.
The North's 60th anniversary comes amid international doubts over its commitment to denuclearization, speculation about the health of its leader and a worsening food crisis.
South Korea said last week the North has begun restoring its atomic facilities in apparent anger over not being removed from a U.S. list of countries that sponsor terrorism.
North Korea - which conducted an underground nuclear test blast in October 2006 - began disabling its main nuclear facilities late last year in exchange for international energy aid and other benefits.