By Gabriela Baczynska
MOSCOW, May 28 (Reuters) - President Vladimir Putin on Thursday declared deaths of Russian soldiers during special operations carried out in peacetime to be classified as a state secret, a move that comes as Moscow stands accused of sending troops to fight in eastern Ukraine.
Putin, who has repeatedly denied any involvement of Russian troopsin a pro-Russian separatist rebellion there, amended a decree that had previously classified as secret deaths of servicemen only during war time.
Asked to explain the rationale behind Putin's move, his spokesman Dmitry Peskov had no immediate comment.
Russia's role in the turmoil in east Ukraine, where more than 6,100 people have been killed in over a year of fighting, has been one of the most contentious issues in a conflict that has thrown ties between Moscow and the West into disarray.
Russian opposition activists released a report this month saying at least 220 serving Russian soldiers were killed in fighting in two hot spots in east Ukraine last summer and earlier this year.
Boris Nemtsov, an opposition leader who initiated work on the report, was gunned down in central Moscow in late February. His close aide who helped finalize the document, Ilya Yashin, told Reuters by telephone: "This shows that the war with Ukraine - undeclared but ongoing - is a major sore spot for Putin.
"This...should be seen as a threat to activists, politicians and journalists who deal with this."
Sergei Krivenko, who heads a soldiers' rights group and sits on the Kremlin's advisory council on human rights, said the pesidential decree was "within the logic of the current situation in Russia"
"If Russian authorities officially say there are no Russian troops in Ukraine, then, all the more so, there can be no losses," he said.
While the decree refers to information held by the defense ministry, Krivenko agreed with Yashin it could be used to exert pressure on activists, politicians and journalists investigating the matter.
They cited the case of Svetlana Davydova, a Russian national charged with treason after calling the Ukrainian embassy to say she had overheard a soldier's conversation about troops from a nearby military base being sent to Ukraine.
TROOPS ON BORDER
Russia annexed Crimea from Ukraine last year after wresting control over the peninsula by deploying troops with no insignia. Moscow initially vehemently denied they were Russian troops.
Putin only publicly admitted Russian soldiers had been deployed in Crimea nearly a month after signing legislation formally completing the peninsula's annexation.
A Reuters reporter witnessed earlier this week the Russian army massing troops without insignia and hundreds of pieces of unmarked weaponry on the border with Ukraine.
Asked by Reuters if this indicated Russia planned an invasion of Ukraine, Kremlin spokesman Peskov told a conference call with reporters: "I find the wording of this question, 'if an invasion is being prepared', inappropriate as such."
A fragile ceasefire has been in force in east Ukraine since February, but each side accuses the other of violations. Kiev fears Russia could commit troops to a push to extend control by separatist forces deeper into Ukrainian territory. (Editing by Ralph Boulton)