Russian photographer Andrei Stenin, missing since early August, has been confirmed dead in Ukraine, the Russia Today media group he worked for announced on Wednesday.

In thick pine forests hidden in the remote wilderness of eastern Lithuania, young professionals are ditching their suits and ties for camouflage gear, and swapping iPads for rifles.

European Union nations will decide on new sanctions against Moscow by Friday, with Russian aggression towards Ukraine requiring the strongest possible response, incoming EU foreign affairs chief Federica Mogherini said.

Leaders of the 28-member EU decided on Saturday to impose a fresh round of sanctions against Russia after alleging that Moscow had deployed troops and weapons to back a rebel counteroffensive in southeast Ukraine.

NATO leaders plan a powerful show of unity at a summit this week against Russia's alleged aggression in Ukraine, but there is little the military alliance can do to intervene.

The announced deployment of thousands of NATO troops and extra military equipment in Eastern Europe is intended to reassure NATO member states in the former Soviet bloc, but is bound to anger Russia, as it will challenge a key NATO-Russia deal.

Fighting in Ukraine has driven over half a million people from their homes, the U.N. refugee agency said Tuesday, warning that the real number could be double that, in a crisis threatening the entire region.

At least 260,000 have been displaced within Ukraine, UNHCR said, adding that Moscow had reported another 260,000 people have sought asylum in Russia.

Ukraine's military on Tuesday reported losing 15 soldiers over the last 24 hours of fighting with eastern insurgents who it claims are backed up by Russian weapons and troops.

Senior defense spokesman Andriy Lysenko said another 49 troops and their accompanying irregular forces had been wounded in various attacks. He did not report losses suffered by the rebels in a campaign that has already claimed more than 2,600 lives.

A comment attributed to President Vladimir Putin warning that Russia could capture Kiev in two weeks was taken out of context, his top foreign policy aide said Tuesday.

Moscow declared NATO a "threat" to its security Tuesday after the Western military alliance announced plans to reinforce defenses in eastern Europe because of Russia's alleged stoking of war in Ukraine.

Moscow's surprise declaration of a shift in its military doctrine came just ahead of a NATO summit in Wales on Thursday at which beleaguered Ukrainian President Petro Poroshenko will lobby U.S. President Barack Obama for military help.

The Ukraine crisis is forcing NATO back to the basics of collective defense in Europe as Russia seeks to restore influence in its Soviet era backyard, analysts and officials said.

NATO leaders meeting Thursday and Friday in Wales must now ensure the alliance can react quickly and credibly after years spent well beyond its original remit -- the defense of western Europe against the Soviet Union, they said. 

U.N. Secretary General Ban Ki-moon warned Western powers Tuesday "there is no military solution" to the Ukraine crisis, as NATO prepares to upgrade its combat readiness in eastern Europe.

Ban said he was greatly concerned at developments in Ukraine and wanted to avoid further deterioration in a crisis "that has been developing into a very chaotic and dangerous situation".