MOSCOW - Russian President Vladimir Putin turned up the heat on Ukraine on Wednesday by threatening to demand advance payment for gas supplies, a move designed to exert economic pressure as Ukraine confronts possible bankruptcy, a mutiny by pro-Russian separatists in the east and a Russian military buildup across the border.
NATO's top commander in Europe warned that the alliance could respond to the Russian military threat against Ukraine by deploying U.S. troops to Eastern Europe, but Putin's latest tactics suggest he may be aiming to secure Russia's clout with its neighbor without invading.
Speaking at a Cabinet session, the Russian leader voiced hope that diplomatic efforts to ease the Ukrainian crisis would yield "positive results," an apparent reference to talks set for next week that will bring together the United States, the European Union, Russia and Ukraine for the first time.
Russia wants the talks to focus on a road map for Ukraine that would include constitutional reforms to turn it into a federation and guarantee its neutral status. Those demands reflect the Kremlin's hope of retaining influence over its neighbor and ensuring it does not join NATO. Ukraine has responded by saying it will not be dictated by Russia.
Taking a tough stance before the negotiations set for next week, Putin instructed the government to be prepared to charge Ukraine in advance for gas supplies - a step that would inflict more pain on a nation already teetering on the verge of bankruptcy. He said the change needed to be taken if "additional consultations" with the European Union fail to yield results.
The Kremlin pressure comes as pro-Russia protesters have continued to occupy government buildings in eastern Ukraine.
Ukraine and the West have accused Moscow of fomenting the unrest to create a pretext for another Russian military incursion similar to last month's takeover of Crimea.
Ukrainian Interior Minister Arsen Avakov said the standoff in Luhansk and the two neighboring Russian-leaning regions of Donetsk and Kharkiv must be resolved within two days.
"I want to repeat that there are two options: political settlement through negotiations and the use of force," Avakov told reporters. "We are ready for both options."