Kiev on Tuesday showed off two purported Russian soldiers it captured during a gun battle in the separatist east that Ukraine's pro-Western leadership says proves the Kremlin's direct involvement in the war.
The two wounded men -- recovering in a Kiev military hospital under the guard of masked state security men -- have turned into pawns in a bitter public relations battle being waged by Moscow and Kiev since Saturday's firefight.
Russia insists that Captain Yevgeny Yerofeyev and Sergeant Aleksander Aleksandrov had been decommissioned from the armed forces by the time Kiev believes they entered the Ukrainian war zone more than a month ago.
Moscow acknowledges the presence of Russian "volunteers" and off-duty servicemen in Ukraine while rejecting charges that they were there under orders from President Vladimir Putin's generals.
But Ukraine's military has released interrogation videos in which the two say they were part of a force of about 200 men contracted to serve with the main military intelligence branch of the Russian General Staff.
The storied unit -- known among global security experts by its Russian acronym "GRU" -- has been one of the most sophisticated and well-equipped branches of the armed forces since Soviet times.
Its presence in Ukraine would suggest that Russia is covertly trying to stoke a separatist conflict that drains Kiev's dwindling resources and further complicates Ukraine President Petro Poroshenko's efforts to move his ex-Soviet country into the European Union and under the military protection of NATO.
Ukraine's military on Tuesday reported the death of four more servicemen in fighting that is once again flaring despite all sides being bound by a new February truce deal.
Kiev's decision to organise an international media visit to the two captives' hospital rooms also threatens to further outrage the Kremlin and harden Putin's stance during international talks on finally resolving the crisis.
US Assistant Secretary of State Victoria Nuland cautioned during a visit to Moscow on Monday that Kiev must respect international laws governing the fair treatment of war captives even as it tries to lay out an irrefutable case against Putin.
Faces shielded from reporters
Both of the men looked wan and disturbed by the media's presence as they lay in their individual rooms dressed in brown hospital-issued pyjamas.
Neither acknowledged their membership in the Russian armed forces nor revealed any details about their service.
"I would like to express thanks to the hospital doctors for their professional help," the bearded Yerofeyev said while shielding his face with his elbow.
The 30-year-old added that he wanted to tell "my relatives that I am fine, alive and well... Of course, it would be good to keep this from getting in the press."
The slightly younger Aleksandrov's face had a yellow tint that signalled a more serious condition. He stared blankly at the media scrum and said little besides expressing a longing to see his parents and wife.
"I will not answer that," he mumbled in response to a direct question about his membership in the Russian armed forces.
Reporters were granted access after the men were visited for about 10 minutes by representatives of European Union and the Organization for Security and Co-operation in Europe (OSCE).
Several members of the Amnesty International human rights group also joined the European inspectors' group.
Amnesty spokesman Bogdan Ovcharuk said the soldiers reported no complaints about their treatment thus far.
"We asked them whether they had been tortured and they said no," Ovcharuk told AFP. "They added that they were satisfied with their (hospital) stay."
Kiev rejects prisoner swap
Kiev authorities said they would put both on a "public" trial for committing acts of terror and return them to Russia if they fully confessed.
But a Russian defence ministry spokesman said the military command in Moscow intended to contact its counterparts in Kiev with a demand to immediately return the captives.
"We are counting on the good sense of the Ukrainian leadership and the speedy release of Aleksander Aleksandrov and Yevgeny Yerofeyev," defence ministry spokesman Igor Konashenkov told the Interfax news agency.
Ukraine's military on Tuesday denied being in touch with the Russians and rejected suggestions from one eastern separatist leader that the men could be released as part of a broader prisoner swap.
"We are not talking about their exchange," Ukrainian army spokesman Andriy Lysenko told reporters.