“Aside for a few marginals, nobody here is going to throw any flowers at Russian tanks,” Mr. Filatov said. He recently persuaded more than 20 local groups, including several pro-Russia outfits that had cheered Moscow’s annexation of Crimea, to sign a declaration in support of Ukraine’s territorial integrity and against Russian aggression.

Pavlo Khazan, a pro-democracy activist here who helped organize a series of rallies against Mr. Yanukovych, said many ordinary people distrusted rich people, including the governor, as a matter of principle. But they realize, he said, “that at this pivotal moment we need a strong guy for the region” who knows how to manage effectively and “doesn’t need to take bribes.”

While Ukraine’s fractious national government in Kiev has been severely rattled by Russia’s seizure of Crimea and its ominous military maneuvers, the Dnipropetrovsk region has moved swiftly to form its own regional defense council, set up reserve command centers stocked with food and water, and devise detailed plans for what officials, police officers, firefighters and other public servants must do in the event of an invasion.

“While they are arguing in Kiev,” Mr. Korban said, “we are preparing for action.”

The ground floor of the regional administration building has been turned over rent-free to a citizens’ defense organization headed by Yuri Bereza, a retired soldier who fought in Afghanistan for the Soviet Army. His group has signed up more than 7,000 volunteers, aged 16 to 78, ready to fight if Russia invades.

The new governor, Mr. Kolomoysky, has dipped into his own pockets to buy $5 million worth of diesel oil, aviation fuel and batteries for Ukraine’s underfunded and ill-equipped military. The gesture impressed Ukrainians more accustomed to officials stealing from them.

Mr. Korban said he had assured employees of the regional administration that no one would be fired for having supported the previous government, or even for past instances of petty corruption, because “they had to work within the system that existed.” If everyone who ever gave or took a bribe were punished, “we would have to put half the country in jail,” he added. “This is a tolerant revolution, a soft revolution.”