Uzbek President Islam Karimov has died after suffering a stroke at the age of 78, three diplomatic sources told Reuters on Friday, leaving no obvious successor to take over Central Asia's most populous nation.

The Uzbek government did not immediately confirm the reports. Earlier on Friday it said in a statement that the health of Karimov, who has been in hospital since last Saturday, had sharply deteriorated.

"Yes, he has died," one of the diplomatic sources said when asked about Karimov's condition.

Earlier Uzbekistan's President Islam Karimov was critically ill, his government said on Friday, which could indicate that Central Asia's most populous nation is preparing for its first transfer of power since independence.

The health of Karimov, 78, had sharply deteriorated over the past 24 hours, the cabinet said in a brief statement published by official newspaper Narodnoye Slovo.