MOSCOW — President Vladimir V. Putin and other senior Russian officials threatened on Wednesday to restrict supplies of natural gas to Ukraine, and they reiterated the Kremlin’s contention that Ukraine owes Russia more than $16 billion in unpaid gas bills and other debts.
The declarations, at a government meeting just outside Moscow, were the latest pointed reminders to the West that Russia holds substantial sway over Ukraine’s financial future — even without a military incursion into eastern Ukraine. The declarations also seemed intended to increase the Kremlin’s leverage in talks with the United States over resolving the political crisis.
“If this critical situation really continues like this, I believe there is every reason to apply the transition to a prepayment system for gas supply,” Prime Minister Dmitri A. Medvedev said, according to a Kremlin transcript of the meeting. Mr. Putin said he agreed, but urged Mr. Medvedev and other officials, as well as Gazprom, the state-controlled energy company, to delay such a move “given the difficult situation in Ukraine.”
In addition to seeking advance payment from Ukraine, at a time when the country is suffering severe financial problems, Russia could cause havoc by simply cutting off the supply of natural gas to Ukraine — a step it took during previous disputes. Russia’s control over Ukraine’s energy supply has long given the Kremlin extraordinary coercive power over its neighbor, which could be left freezing in winter. The Kremlin has followed its invasion and annexation of Crimea last month in southern Ukraine with warnings that it could intervene militarily to protect ethnic Russian people living in eastern Ukraine.
Russia has also exerted economic pressure, essentially pointing out that it could claim to be owed debts from Ukraine nearly equaling the $18 billion financial assistance package that the International Monetary Fund recently agreed to provide to the government in Kiev.
The provisional authorities in Kiev have scheduled a presidential election for May 25 to replace Viktor F. Yanukovych, who fled in late February and was stripped of power by the Parliament in a move that Russia says amounted to an illegal coup.
So far, there is no pro-Russian candidate with any chance of winning. In what appears to be an acknowledgment of that reality, the Kremlin has been calling for structural political changes in Ukraine that would substantially weaken the central government in Kiev.