Uzbek President Islam Karimov, one of Asia's most authoritarian leaders, has died, Turkey says - despite no official Uzbek confirmation.
Mr Karimov, 78 and in power since 1989, was taken to hospital last week after a brain haemorrhage but the government has only said he is critically ill.
On Friday, Turkish Prime Minister Binali Yildirim told a televised meeting Mr Karimov had died.
Uzbek state TV channels have dropped light entertainment programmes.
Mr Karimov has no clear successor. There is no legal political opposition and the media are tightly controlled by the state.
A UN report has described the use of torture as "systematic". Mr Karimov often justified his strong-arm tactics by highlighting the danger from Islamist militancy in the mainly Muslim country, which borders Afghanistan.
"Uzbek President Islam Karimov has passed away," Turkish Prime Minister Binali Yildirim said in a cabinet meeting broadcast live.
"May God's mercy be upon him, as the Turkish Republic we are sharing the pain and sorrow of Uzbek people."
Long before Mr Yildirim's statement, rumours were circulating that Mr Karimov had already died. He had not appeared in public since 17 August.
Earlier on Friday, Reuters news agency said three unnamed diplomatic sources had confirmed his death.
A Russian-based opposition website, Fergana, reported that preparations were under way for his funeral in his home town, Samarkand.
Samarkand's airport has been closed to scheduled flights on Saturday.
How rumours grew:
- Sunday: President Karimov "receiving inpatient treatment", Uzbek Cabinet of Ministers announces
- Monday: Daughter Lola Karimova-Tillyaeva writes on Instagram that he suffered a brain haemorrhage
- Wednesday: Government cancels some celebrations for independence day on Thursday
- Thursday: Mr Karimov's independence day speech read out on state TV by a presenter
- Friday: Government says Mr Karimov's condition has sharply deteriorated
Some human rights groups say the Uzbek government is one of the most repressive in the world, notably after a crackdown in the eastern city of Andijan in 2005, when hundreds were killed.
Mr Karimov's followers argue that curbs on freedom are a small price to pay for law and order.
"Yes of course, it's a price for stability, because we see what is happening now in Syria, in Iraq, in Yemen, in Afghanistan and even in Europe - you cannot defend yourself from the terrorist attacks," Sherzod Igamberdiev, a lawyer in Tashkent, told BBC News.
"If you put all your efforts into stopping terrorism, you will have criticism, but we live here, we know the situation on the inside, we are satisfied with him, we love him."
Uzbekistan was long one of Russia's strongest allies among other former Soviet states but strains appeared in recent years, notably when Tashkent suspended its membership of a Russian-led military alliance, the Collective Security Treaty Organisation.
Analysts say Mr Karimov has played Russia, China and the West against each other to keep Uzbekistan from total isolation and to receive limited US aid. In 2014, Russia wrote off most of Uzbekistan's foreign debt to Moscow, forgiving $865m.
Russian presidential spokesman Dmitry Peskov said on Friday the Kremlin had no confirmation Mr Karimov might be dead.