Authoritarian Uzbek leader Islam Karimov is in stable condition in an intensive care ward after suffering a brain haemorrhage on Saturday, his daughter said.
President Karimov (78), who has run Uzbekistan since it was a Soviet republic and wields sweeping powers, has no obvious successor, a situation characteristic of the volatile Central Asia region which is still largely run by former Communist apparatchiks.
The Central Asian country is a stage for strategic rivalry between Russia, China and the West.
The absence of a strong political opposition or free media means any eventual transition of power is likely to be decided within a close circle of Mr Karimov’s family and top officials.
"At the moment, it is too early to make any forecasts about his condition in the future," his daughter Lola Karimova-Tillyaeva wrote on her Instagram page on Monday. "I will be grateful to everyone who will support my father with prayers."
The government of Central Asia’s most populous country, with reserves of oil, gas and gold, said on Sunday Karimov was undergoing hospital treatment, but gave no details.
A failure to reach consensus on a transition could destabilise a mostly Muslim nation of 32 million long targeted by Islamist militants and strategically located north of Afghanistan, in the resource-rich region where Russia, China and the West vie for influence.
Since Uzbekistan became independent with the 1991 collapse of the Soviet Union, Karimov has with some success courted both the West and Russia as well as China, maintaining political and economic links with all.
Human rights
Mr Karimov has been criticised by rights groups and some governments over his human rights record, but argues the country is at risk of becoming a conduit for Islamist militants from Afghanistan to Russia and western Europe. The Uzbek government has accused Islamists of being behind protests in the city of Andizhan where police and security forces fired into a crowd in 2005, killing 187 people, according to official reports.
Mr Karimov has no sons, who might have been regarded as heirs apparent in the patriarchal culture. His elder daugher, Gulnara, has not appeared in public since several media reported in 2014 that she had been placed under house arrest.
Mr Karimov’s second daughter, Lola, is Uzbekistan’s ambassador to Paris-based UNESCO.
Among Uzbekistan's ex-Soviet neighbours, only Turkmenistan, a more wealthy gas exporter with a much smaller population, saw a relatively smooth transition when its Soviet-era leader Saparmurat Niyazov died in 2006. Kurbanguly Berdymukhamedov, then deputy prime minister, took over.
Poorer Kyrgyzstan, on the other hand, has gone through two violent revolutions accompanied by ethnic clashes.
Another neighbour, Tajikistan, went through a devastating civil war in the 1990s after Soviet institutions crumbled.
Some of those who fought against the Tajik government at the time were members of the Islamic Movement of Uzbekistan, a group which has been outlawed and has pledged allegiance first to the Taliban and then to the Islamic State.