MOSCOW (CNN) -- Boris Nikolayevich Yeltsin announced on national television Friday that he had resigned and presidential elections will be held within 90 days to replace him.

The announcement caught Russia by surprise, and is likely to launch the country into yet another political crisis as parties scramble for unexpected presidential elections.

Looking pale and grim in a speech on national television, Yeltsin, 68, said he had turned over his powers to Prime Minister Vladimir Putin, his preference to succeed him as president.

The Communist party maverick who swept into power as a post-Soviet reformer, had suffered from serious respiratory and heart ailments for much of his presidency. Widespread poverty and dissatisfaction reduced Yeltsin's popularity in recent years,
but Russians hailed him as a hero when the Soviet Union crumbled in 1991.

Despite declining health, Yeltsin occasionally flashed the same iron resolve that squelched an attempted coup during the Soviet twilight, if only to rise from his sickbed to fire yet another Cabinet minister. Or in the case of Chechnya, order another war against separatists. Unlike a disastrous war earlier this decade in the breakaway Republic, Yeltsin's latest campaign, still ongoing, enjoys broad support among Russians, perhaps his final popular act as president.