Russia has sent thousands of additional troops to its border with Ukraine following the Kiev leadership's announcement that it will sign an economic association pact with the European Union next week.
The NATO chief reporting the renewed Kremlin troop buildup called it "regrettable" and warned that it might be a prelude to an invasion by Russia should the separatist rebellion fail to wrest from Kiev's control the Russian-speaking regions of eastern Ukraine, where vital military hardware is produced for Russia.
It was the decision by then-President Viktor Yanukovich to scrap the European Union association agreement in November that ignited rebellion in Ukraine. Pro-Europe demonstrators angered over his move to keep Ukraine in Russia's economic orbit ousted Yanukovich in February, setting off Russia's seizure of the Crimean peninsula and the separatist battles raging in eastern Ukraine.
Russian President Vladimir Putin warned in an address to agricultural industry leaders on Wednesday that Ukraine's refusal to join the Russia-led Eurasian Union — the economic alliance he created to rival the EU — threatened the customs-free trade between the two former Soviet republics, especially imperiling the market for farm products.
"This doesn't have anything to do with politics or with the options one or another state selects, because each sovereign state has the right to choose its original pathway," Putin said in an apparent attempt to preempt Western accusations that he was trying to pressure Kiev to abandon alliance with the Western European bloc.
But Putin's comments followed by mere hours Ukrainian President Petro Poroshenko's announcement that he would sign the economic pact on June 27 during a Ukrainian-EU summit in Brussels.
Putin "stressed Russia's right to defend its own economic interests," the Voice of Russia said of the Kremlin leader's address to an agricultural forum in the southern farm belt center of Stavropol.
Russia maintained more than 40,000 troops along its border with Ukraine over the past three months but had reportedly begun withdrawing them to their bases ahead of Poroshenko's June 7 inauguration. However, NATO Secretary-General Anders Fogh Rasmussen said during a London visit Thursday that the alliance has observed a fresh buildup of thousands of additional troops along the border.
"I consider this a very regrettable step backward. It seems Russia keeps the option open to intervene further in Ukraine," Rasmussen said in an exchange with journalists after a speech at London's Chatham House think tank. He warned that NATO "would have to respond in a firm manner" if Moscow further interferes in the conflict convulsing eastern Ukraine.
Russian media reported Thursday that Putin had agreed with European Commission President Jose Manuel Barroso to engage in three-way talks with the EU and Ukraine "in the context of the forthcoming signing of the EU-Ukraine Association Agreement." The reports gave no further details of Russia's agenda in the talks reportedly to start with economic experts from each of the three participants.
As the leaders and diplomats weighed in on Ukraine's economic reorientation, fighting between government troops and the pro-Russia rebels in the east continued despite Poroshenko's offer this week of a unilateral cease-fire. Separatist leaders in Donetsk and Luhansk regions, which are home to 6.5 million people, rejected his call to surrender their arms and negotiate their grievances in a peaceful and European-mediated forum.
Russia Today television reported a sharp worsening of the "humanitarian crisis" confronting those living in the embattled eastern areas, where water and power supplies have been disrupted in rebel-occupied towns and a gas shortage hampers emergency medical aid and civilian evacuations.
The state-controlled broadcaster also reported an "unprecedented" exchange of bodies of those killed in recent clashes, including the 49 Ukrainian troops who perished when rebels shot down a transport plane Saturday. Russia Today film showed unarmed men carrying white flags meeting on a bridge near Donetsk as trucks with containers said to be bearing corpses crossed the span.
Meanwhile, government troops attacked separatist positions in the village of Yampil, near Donetsk, at dawn in a massive incursion involving at least 20 tanks, said Igor Strelkov, the Russian former special forces officer in command of separatists in the Donetsk region, the Reuters news agency reported.
"Our people are holding but we can't rule out that they [government forces] will break through," Strelkov said in a video statement, reporting "heavy losses" in the battle. He urged the Kremlin to "take some measures" to protect the separatists fighting to join their seized territory to Russia.
Reuters also quoted one military source as saying the separatists had amassed 4,000 gunmen for an impending showdown with government forces.
"Then there will be 4,000 coffins," Ukrainian military spokesman Vladyslav Seleznyov replied when asked about the report during his daily radio briefing of reporters in Kiev.