A.T.M.'s have been empty as banks, most based in mainland Ukraine, face obstacles delivering currency, and grapple with mounting concerns about long-term business risks. If world leaders refuse to recognize Russia’s annexation of Crimea, flights could be restricted for years, as they are in northern Cyprus, which has direct air links only with Turkey.

At a minimum, Kiev’s strong leverage over utilities and other vital services stands to force the Kremlin into negotiations with the new Ukrainian leaders whom Mr. Putin has denounced as illegitimate and has so far refused to meet.

Last week, in a meeting with the country’s top economic officials, including the ministers of finance and economics and the head of the central bank, Mr. Putin expressed his own concerns about Russia’s financial prospects.

“Let me say that the current and forecast growth rates the government has given cannot satisfy us in any way,” he said, according to a Kremlin transcript. “We must step up the pace of development.

“Above all, we need to maintain the existing general macroeconomic stability,” Mr. Putin said. “We need to be ready to respond rapidly to both internal and external risks — and they are not getting any fewer — ensure that the budgets at all levels are executed and keep inflation at an acceptably low level.”

Mr. Slyunayev, the regional development minister, said he believed that the government in Kiev would be reasonable and not cut off essential services but might begin charging for water and electric service. “Ukrainian authorities will not provoke a humanitarian crisis,” he told Kommersant.