Uzbek President Islam Karimov has been taken to hospital, the government says, amid rumours that he is seriously ill.
A statement said he was undergoing a full examination and treatment would "take a certain period of time", without giving further details.
Mr Karimov, 78, has been leader of the former Soviet republic since before independence in 1991.
He is known to have health issues, but the government has never previously issued a statement about his health.
Unconfirmed reports quoted by the Fergananews website said that Mr Karimov had suffered a stroke.
He was last seen on state TV on 17 August meeting the South Korean interior minister.
Independence Day celebrations - which the president always attends - are to be held on 1 September.