Pro-Russian separatists raised the Russian flag on Ukrainian army armored vehicles in eastern Ukraine on Wednesday, mocking the pro-Western Kyiv government's attempt to reassert control on the eve of crucial talks in Geneva on the country's future.
A Ukrainian defense ministry statement confirmed that six armored personnel carriers were seized with the help of Russian agents, Reuters reported.
The defense ministry statement said the troop carriers are now in Slovyansk, guarded by "people in uniforms who have no relation to Ukraine's armed forces."
Meanwhile, Ukraine's counter-intelligence chief said he has evidence of Russia's involvement in eastern provinces. According to Reuters, Vitaly Nayda told a news conference Wednesday that the determination was made after intercepting conversations of the Russian military from Sloviansk. The official said 40 agents 'recruited by Russian security services' had been arrested. Nayada added that those arrested had admitted to being recruited and were now assisting with the investigation.
Amid escalating rhetoric between Moscow and Kyiv, the incident in Slovyansk highlighted defiance by pro-Russian separatists, undermining the central government efforts to push armed rebels out of captured buildings in 10 eastern towns without bloodshed.
Government troops had driven armored personnel carriers flying the Ukrainian flag into the town of Kramatorsk in the early morning after securing control of a nearby airfield from the rebels on Tuesday, prompting Russian President Vladimir Putin to warn of the risk of civil war.
As the armored vehicles drove into Slovyansk waving Wednesday, some people waved back and shouted: "Well done lads!" and "Russia, Russia!"
A soldier guarding one of the carriers now under the control of the rebels told Reuters he was a member of Ukraine's 25th paratrooper division from Dnipropetrovsk.
"All the soldiers and the officers are here. We are all boys who won't shoot our own people," he said, adding that his men had no food for four days until local residents fed them.
A spokesman for the separatists and a witness in Kramatorsk said the Ukrainian troops had given up their vehicles to the rebels after talks.
Overhead, a Ukrainian jet fighter carried out several minutes of aerobatics above the town's main square in a show of strength by Kyiv's forces.
The muscle-flexing and inflamed rhetoric heightened fears of violence.
The Kyiv government is seeking to reassert control slowly and without bloodshed before Thursday's Geneva meeting at which the Russian and Ukrainian foreign ministers are due to meet for the first time in the presence of the United States and the European Union.
Russia, which has refused to recognize Ukraine's pro-Western government since Moscow-backed President Viktor Yanukovych was ousted by mass protests in February, sought to dramatize instability in its neighbor ahead of those talks.
NATO bolsters security
A column of combat vehicles with a Russian flag on the front one makes its way to the town of Kramatorsk, Ukraine, April 16, 2014.
A combat vehicle with gunmen on top makes its way through a checkpoint to the town of Slovyansk, Ukraine, April 16, 2014.
A masked gunman guards combat vehicles with Russian, Donetsk Republic and Ukrainian paratroopers, flags and gunmen on top, Slovyansk, Ukraine, April 16, 2014.
Local residents bring flowers to place them on armored personnel carriers in Slovyansk, Ukraine, April 16, 2014.
Masked pro-Russian gunmen attack a photojournalist near combat vehicles flying a Russian flag, in Slovyansk, Ukraine, April 16, 2014.
An Orthodox icon is displayed on barricades in front of a city parliament in Slovyansk, Ukraine, April 16, 2014.
A woman cleans up trash in front of an entrance to a city administration building in Slovyansk, Ukraine, April 16, 2014.
Ukrainian servicemen look at a Ukrainian military jet fly above them while they sit on top of armored personnel carriers in Kramatorsk, Ukraine, April 16, 2014.
A Ukrainian Army helicopter flies over a column of Ukrainian Army combat vehicles on the way to the town of Kramatorsk, Ukraine, April 16, 2014.
NATO Secretary-General Anders Fogh Rasmussen says the alliance has decided on a series of immediate steps to reinforce its military footprint in eastern Europe, in response to Russia's moves.
"We will have more planes in the air, more ships on the water, and more readiness on the land," he told a news conference after the decisions were taken by NATO ambassadors.
"For example, air police and aircraft will fly more sorties over the Baltic region," he said, "allied ships will deploy to the Baltic sea, the eastern Mediterranean, and elsewhere as required."
Constant Brant, a NATO Public Affairs Officer in Brussels, said details of the deployment were still being worked out and that Allied Commander Philip Breedlove was expected to make an announcement regarding the make-up of the force in the coming days.
Putin: Ukraine on brink of civil war
Russian President Vladimir Putin said the growing crisis in Ukraine has brought the country to the brink of civil war.
The Kremlin said Putin made the comment during a telephone call Tuesday with German Chancellor Angela Merkel.
President Putin accused the Ukrainian government of pursuing an "anti-constitutional" path by using force against the pro-Russian demonstrators who have taken over official buildings in 10 southeastern Ukrainian towns and cities.
The Kremlin says Russian and German leaders hope Thursday's talks in Geneva will show the importance of finding a peaceful solution.
Putin is scheduled to speak on Thursday at an annual question and answer session with citizens, which could signal how far he intends to go in Ukraine.
Some information for this report provided by Reuters