The quirky mayor of Kiev has raised plenty of eyebrows with colorful behavior in public — and just as many by vanishing from view for weeks.

Ukrainian officials have a hard time remembering the last time they saw Mayor Leonid Chernovetsky, whose antics have earned him the nickname of "Cosmos."

But the mayor also has been the target of crackdowns by the central government, and that could have motivated Cosmos to stay out of sight.

City administration head Oleksandr Popov says he last met with the mayor toward the end of 2010. The disappearance stretched out so long that Prime Minister Mykola Azarov instructed Popov two weeks ago to track down the mayor and get him back to work.

"Be sure to find him. Tell him that Kiev residents have been missing him," Azarov told Popov. After that order, a joke spread widely, asking: "Can Kiev really afford a cosmic expedition?"

Chernovetsky's spokeswoman Marta Hrymska told The Associated Press in a phone text message Tuesday that the mayor is back on the job after a vacation in Georgia. But she did not pick up the phone for elaboration, stating in the message only that Chernovetsky planned no public appearances.

His sudden shyness is deeply out of character for a man who liked the limelight so much that his detractors suggested he was mentally unbalanced. Some observers suggest the disappearance is connected to a struggle with President Viktor Yanukovych over control of Kiev's assets.

Chernovetsky was elected mayor in 2006 in what his opponents say was a dirty campaign marred by bribing impoverished elderly voters with food. Chernovetsky denied those allegations, but has acknowledged giving millions in bribes during his days as a businessman.

He has sung at rallies and offered to auction off his kisses. That behavior prompted some officials to call for a medical examination into whether he is mentally healthy to govern the city.

In response, Chernovetsky posed in tight swimming trunks in front of scores of reporters to try to show he was both physically and mentally fit.

This fall, Yanukovych fired him as the head of the city administration and installed trusted ally Popov in his place. Chernovetsky remained the city mayor, but it was Yanukovych's team that was seen as calling all the shots in the city. The two positions are separate, but the duties often overlap.

The government then opened several investigations into the allegedly illegal sale of city land and property by Chernovetsky's top officials. Opponents say the mayor embezzled billions of dollars by selling Kiev land to friendly companies and persons.

Soon, the mayor went missing. Rumors swirled as to where Chernovetsky might be, with some speculating that he was seeking political asylum in Israel or that he had secretly tendered his resignation.

Commentators suggested that by failing to fulfill his duties, Chernovetsky was trying to force the president to stop the investigations into his close aides. Yanukovych is reluctant to see Chernovetsky go just yet and share power with a new mayor, because his protege Popov, is currently unlikely to get elected.