Uzbekistan's Islam Karimov is in critical condition after a stroke, the government has said, which could mean that Central Asia's most populous nation is preparing for its first transfer of power since independence.

The health of Karimov, 78, sharply deteriorated over the past 24 hours, the cabinet said in a brief statement on Friday.

"The doctors assess (his health) as critical," the statement said, adding Karimov has been in hospital since Saturday.

Several other media outlets, including Russian news agency RIA and Uzbek news website, also ran reports quoting the same statement.

Uzbekistan celebrated its Independence Day on September 1 with Karimov notably absent from the celebrations, causing speculation over his health.

Several reports, which were later officially denied, claimed he had died on August 29.

Karimov has ruled Uzbekistan in an authoritarian style since 1989, first as a Communist leader, and then as president after the Soviet Union fell in 1991.

Source: Agencies