Angered by major price hikes for public transport, utilities and medical care, the protesters demanded that mayor Leonid Chernovetsky resign.

But so far the 57-year-old has proved highly resilient, despite widespread accusations of corruption and erratic behavior often bordering on the absurd.

He survived an early vote last year that was initiated by Ukraine's parliament in an attempt to unseat him. He is now fending off an investigation over controversial sales of city land and even a parliamentary inquiry into whether he is mentally fit to hold office.

Eager to demonstrate he is of sound body and mind, he invited journalists to watch him earlier this month jogging, doing chin-ups and diving into a swimming pool in his tight Speedo suit.

''They are judging me today,'' Chernovetsky said, after he emerged from the water and flexed his muscles in front of the cameras. ''They want me to spend my whole life behind bars in a psychiatric ward. I want to demonstrate to the whole world that I am completely healthy, both physically and psychologically.''

Chernovetsky says his nickname is derived from his policies, which are ''cosmic'' and ''completely unusual for Ukraine.''

''I am proud that they don't resemble anything that went on in Ukraine before,'' he said on a talk show last year.

Chernovetsky was elected Kiev mayor in 2006 in a surprise win over the capital's incumbent mayor and boxing heavyweight champion Vitaly Klitschko.

His critics charge he won the race through questionable tactics such as donating pasta, sugar and other food to Kiev's impoverished pensioners. He was re-elected last May, largely due to his opponents' failure to unite behind a single candidate.

Chernovetsky has acknowledged on national television that he had given bribes worth $21 million when he was a businessman in the early 1990s. But he denies bribing his voters, calling himself ''the humble mayor who loves babushkas.''

In an effort to increase city revenues, he has proposed charging foreigners to live here, selling his kisses in a lottery and introducing entry fees for visits to city cemeteries. He has also started holding $100,000 dinners for entrepreneurs interested in discussing their affairs with city authorities.

Chernovetsky's opponents have acccused his administration of giving away or selling through non-transparent auctions about 300 plots of land worth several billion dollars in late 2007. Klitschko filed a lawsuit to invalidate those deals, but it was turned down by a Kiev court. Parliament is now investigating those transactions.

Ukraine's competitive elections for president, parliament and Kiev mayor are a testament to the level of democracy in this former Soviet state of 46 million, a sharp contrast to the carefully managed elections in neighboring Russia and Belarus.

But many Kiev residents have had enough, saying Chernovetsky's bizarre policies were bad before but have become unbearable during an economic crisis that is one of the worst in Europe.

About 2,000 elderly women, students and bus drivers from all political groups waived flags in front of Chernovetsky's office Thursday and chanted ''Down with the mayor!'' The drivers parked dozens of buses on Kiev's main streets, blocking traffic to protest job layoffs.

''It's not that he doesn't respect us, it's that he is mocking us!'' said Dmytro Antonenko, a 50-year-old teacher. ''We like him as a singer, but as a singer only.''

Chernovetsky brushed off the protests, saying he was open to dialogue with residents and had set up a complaint line that receives some 9,000 calls a day.

''He believes this demonstration was a political provocation by his opponents,'' said spokeswoman Oksana Makarchenko.

Chernovetsky vowed he would not be intimidated and said he still planned to run for president in an election expected in early January.