MOSCOW -- The president of Uzbekistan, a white-haired man in a suit, rose from his seat at an annual spring festival and swung his hips, clapped his hands and danced a vigorous little jig.
This was nothing out of the ordinary; President Islam Karimov, who is 75 and has ruled Uzbekistan, the most populous country in the former Soviet Central Asia, since before the collapse of Communism, dances every year for Nowruz, the Persian spring holiday celebrated throughout the region.
For eight days after this year's televised event, however, Mr. Karimov disappeared from public view and a disputed report surfaced that he had suffered a heart attack on the day of the dance, March 19. The heightened possibility that a leader who has been in power for more than two decades could suddenly die in office underscored the uncertain politics of succession in Uzbekistan.
State television broadcast archival footage of the leader, never a good sign. His oldest daughter, Gulnara Karimova, 40, seen as a leading figure in what some analysts say is a succession struggle already under way, resigned as envoy to the United Nations in Geneva on Tuesday, possibly positioning herself for a larger role at home. Uzbek exiles reported political paralysis, citing people inside the government.
The rumors in the nation of 30 million people highlight a broader, looming political quandary in former Soviet states from Russia to Tajikistan, where the absence of real elections has meant that succession becomes an unpredictable, hair-raising event.
It is important for the United States because Uzbekistan has been a partner of convenience in supplying American and NATO troops in neighboring Afghanistan. And over the next two years NATO forces in Afghanistan are expected to remove about 70,000 vehicles and 120,000 shipping containers. That operation will require rail lines and well-surfaced roads, something Uzbekistan has to offer as an alternative to Pakistan.
Uzbekistan, a country of apricot orchards, cotton fields and ancient stone cities in the foothills of the Pamir Mountains, has no tradition of democracy, having been ruled by vassal khans of the czars until the Soviet period, and by Mr. Karimov after that. It is unclear now whether it will have a dynastic succession with the rise of a leader's child, as in North Korea, or whether power will pass to a government insider.
The country is an international pariah, and its politics are usually a black box. It has been under United States sanctions since 2004, when human rights investigators determined that political prisoners had died after being immersed in scalding water -- in fact, after being boiled alive.
A debate opened among Uzbek exiles over whether the report that the president had suffered a heart attack, posted on March 22 on the Web site of the opposition People's Party of Uzbekistan, was genuine or was intentionally floated by one of the potential successors within the government.
It continued after Mr. Karimov appeared briefly on television on March 27 in a meeting with Kazakhstan's foreign minister, which was seen as an unconvincing demonstration of his good health.
"He could be sick or it could be deliberate rumors," Shahida Tulaganova, an Uzbek opposition journalist, said in a telephone interview from London. "The probability of the second scenario is greater, but we don't know. It's making a lot of people nervous."
The People's Party leader, Mukhammad Salikh, said in a telephone interview that his source within the president's entourage was motivated not by intrigue but by a simple desire to get out the truth. "They wanted to hide this fact, but we learned about it," Mr. Salikh said.
In the world of Uzbek politics, family ties are never far from the surface.
Prime Minister Shavkat Mirzayev, another leading contender for succession, is seen as having Moscow's backing after his nephew last October married the niece of Russia's richest man, Alisher Usmanov, who is of Uzbek origin and close to the Kremlin.
"That was a good alliance," said Ms. Tulaganova, the Uzbek opposition journalist.
But the reputed Western-leaning candidate, Rustam Azimov, a deputy prime minister and former banker, is said to have wide support in Tashkent, the capital.
According to the Uzbek Constitution, if the president dies in office, the speaker of the Senate becomes the acting president and new elections are to be called.
But a leadership change in neighboring Turkmenistan showed that former Soviet states are not always bound by legal documents. When Saparmurat Niyazov, Turkmenistan's dictator who went by the nickname Turkmenbashi, died in December 2006, the speaker of Parliament was the constitutionally designated successor. But other factors decided the outcome. The police quickly arrested the speaker and a former dentist, Gurbanguly Berdymukhammedov, who had risen to prominence by replacing Soviet-era gold crowns with more naturally appearing composite materials, emerged as the new leader.
The report about the Uzbek president's health, said Danil Kislov, the editor of Fergana News and an authority on Central Asian politics, seems intended to compel Mr. Karimov to designate a successor and head off a similar struggle for power. "If no heart attack happened, one would have to be invented," for this purpose, Mr. Kislov said.
Mr. Karimov's daughter was the most outspoken in refuting the report.
In a post on Twitter on March 26, Ms. Karimova wrote: "Don't try to grate on my nerves with this lowly talk," and "Smn should be more than crazy to say so after seeing OUR PRESIDENT dancing."
One important indicator of the veracity of the disputed report may come in mid-April, when Mr. Karimov is reportedly scheduled to visit President Vladimir V. Putin of Russia in Moscow. If he cancels the trip, it will raise more suspicions.
This article originally appeared in The New York Times.