Nearly $700 billion is owed to Western banks, economists said, much of it by the giant state-run companies that constitute the heart of the Russian economy. But sanctions imposed by the United States and Europe over Russia’s annexation of Crimea and adventurism in southeastern Ukraine have blocked access to Western financing.

Despite Moscow’s plans to turn East as an alternative, China’s banks just do not have the capacity. Instead, the debt threatens to drain the Kremlin of its $400 billion in foreign currency reserves.

Among the companies with their hands out are Rosneft, Novatek, VTB Bank, Rusnano and Russian Railways, asking for sums well beyond the $90 billion held by the National Welfare Fund, a sovereign wealth fund for rainy days.

Mr. Putin has yet to express publicly how he expects Russia to emerge from its financial problems. At a news conference last month, he addressed concerns about oil by saying that prices had been high enough in the first part of 2014 to finance much of the Russian budget, and that the country would just have to “wait and see” about next year.

He also tried to portray the large drop in value of the ruble as useful. “We used to sell by the dollar and get 32 or 35 rubles in return, but if you look at today’s exchange rate, we get 45, 47 or 48 rubles for every dollar’s worth of what we sell,” he said, and the ruble has reached 54 to the dollar since Mr. Putin spoke. “In that sense, budget revenue has even increased.”

Image Bad economic news challenges Russia’s president, Vladimir V. Putin. Credit... Associated Press

Vedomosti, the main business daily, published an excoriating editorial on Tuesday comparing Mr. Putin to President Robert Mugabe of Zimbabwe, who the editorial said did basically nothing as the exchange rate there fell to four trillion Zimbabwe dollars for one American dollar.