Uzbekistan's government has issued an unusual statement announcing the hospitalization of President Islam Karimov, who has ruled the former Soviet republic in Central Asia for more than 25 years.

Sunday's statement gives no details about the nature of the illness, saying only that specialists are giving the 78-year-old president a full medical examination and subsequent treatment will require "a certain amount of time."

Karimov, who tolerates no dissent, has ruled Uzbekistan since Soviet leader Mikhail Gorbachev made him the republic's Communist Party chief in 1989. In December 1991, just days after the Soviet Union ceased to exist, Karimov was elected president of the newly independent state.

As he has aged, questions have been raised both about a successor and the long-term stability of the strategically placed Central Asian country.