WASHINGTON – The prospect of conflict in eastern Ukraine prompted emergency talks in Geneva on Thursday, where the US, Russian Federation, European Union and Ukraine itself ostensibly agreed on a political structure to de-escalate the crisis.Russia agreed that the Organization for Security and Cooperation in Europe should moderate future crisis talks, in an attempt to temper tensions along its border with Ukraine. Russia has amassed over 40,000 troops along that border, equipped for a long stay and prepared to invade its neighbor to the West within mere hours.The United States and NATO responded on Thursday to that buildup with military steps they consider defensive. The Pentagon announced that the US would bolster nonlethal aid to Ukraine, as the Western military alliance moved rapid-response ships to the Baltic Sea.As talks were under way, Ukraine’s government announced that it would restrict border access to Russian men “of an active age,” in an effort to mitigate the threat of further provocation. Moscow threatened retaliation after the announcement.Eastern Ukrainian cities populated by ethnic Russians have experienced protests ever since Moscow’s March 21 annexation of the Crimean Peninsula.Ukrainian police outposts have been attacked, Russian flags have flown from state-run buildings, and three men were killed on Thursday – the bloodiest day yet since Crimea was seized.Moscow says Russia has an obligation to protect ethnic Russians, and that it is prepared to use force to do so. But the Obama administration says that the Russian intelligence agency has fomented tension in eastern Ukraine, with unmarked agents operating throughout the region, attacking outposts and disseminating Russian propaganda.After talks in Geneva on Thursday, US Secretary of State John Kerry said the government in Kiev was prepared to conduct elections across Ukraine’s east that would provide its citizens – some of whom have cultural ties to Russia – with a level of autonomy far greater than that which Moscow grants any Russian region.Crimea “was taken illegally against the constitution of Ukraine and against international law,” Kerry told the press when asked about the Russian occupation and annexation of the peninsula in March.But world powers “didn’t come here to talk about Crimea,” Kerry added. Rather, the four parties were engaged in talks in Switzerland to avoid further deterioration of the conflict – a descent into the “abyss,” as Russian President Vladimir Putin described it on Thursday.“Instead of realizing that there is something wrong with the Ukrainian government and attempting dialogue, they made more threats of force... another very grave crime by Kiev’s current leaders,” Putin said in his annual televised question- and-answer session with the Russian public.“I hope that they are able to realize what a pit, what an abyss the current authorities are in and dragging the country into,” said the Russian president, who reserved the right to use military force while still saying he preferred dialogue.He said that the US position on Russia’s actions in Crimea was “hypocritical” and had brought relations between the two nations to their worst level since the Cold War.“The United States can act in Yugoslavia, Iraq, Afghanistan and Libya, but Russia is not allowed to defend its interests,” Putin said. “To a certain extent, trust has been lost, but we do not think we are to blame.”Meanwhile, in Washington, US President Barack Obama decided to expand nonlethal aid to the Ukrainian military to include medical supplies, sleeping mats and helmet gear for its troops, Defense Secretary Chuck Hagel announced on Thursday.Hagel voiced deep concern over “Russia’s ongoing destabilizing activities in eastern Ukraine.”Reuters contributed to this report.