President Vladimir Putin on Friday sad Moscow would fulfil its obligations to send natural gas to Europe but also said the United States had no business interfering in Russia's talks with Europe over Kiev's debt.
"We certainly guarantee the fulfilment of our obligations before our European customers in full," Putin said in comments released by the Kremlin. "The issue is not about us, the issue is about securing transit through Ukraine."
Putin on Thursday sent a letter to the heads of 18 European countries that receive Russian gas, saying Moscow could turn off supplies because Kiev has so far failed to repay its $2.2 billion energy bill.
He urged immediate talks, suggesting that Europe help pay Ukraine's debt.
Washington condemned Russia's efforts to use energy as "a tool of coercion against Ukraine".
But Putin on Friday suggested that Washington had no business meddling in European affairs.
"It's strange because reading other people's letters is not good. I did not write to them, I wrote to the consumers of gas in Europe," he said at a meeting of his Security Council.
"Everyone is used to the fact that our American friends are eavesdropping but peeping is really not nice (too)," he quipped.
Putin said the fact that Ukraine has not yet settled its gas debts was "absolutely intolerable".
The Russian strongman also suggested that Washington follow up its promises of support with real action.
"Pies on the Maidan will not be enough," Putin said. "This is not enough to deter the Ukrainian economy from slipping into complete chaos."
The assistant US secretary of state, Victoria Nuland, was seen in December distributing cookies to pro-Western Ukrainian protesters in Kiev in a gesture of support.
Moscow has repeatedly slammed Washington for publicly supporting the protesters who in February ousted pro-Russian President Viktor Yanukovych from power