"Let's say we didn't buy them in a shop," said a masked gunman lounging against the side of one of the vehicles. "We came by them in the course of things, if you know what I mean."
The pro-Russian gunmen showing off their prizes in the square claimed that the Ukrainian crews had defected. Other reports suggested they were forced to surrender.
Read more:
• Ukraine bares teeth against eastern uprising
• Ukraine 'on the brink of civil war' - Medvedev
Either way, their presence in the park yesterday afternoon was a propaganda coup for the separatists and an unmitigated humiliation for Ukraine's post-revolutionary government.
About 40 Ukrainian servicemen were later put on buses out of town, suggesting that they, at least, had not changed sides. "They made a decision to give us their vehicles," said a gunman who gave his name only as Vladimir and said he was an army veteran from Donetsk.
A soldier from the Ukrainian Army speaks with local residents in the town of Kramatorsk. Photo / AP
A few kilometres away, another 15 armoured troop carriers full of Ukrainian paratroopers were surrounded and halted by a pro-Russian crowd at Cholkino, a town near an airbase. As the standoff developed, attack helicopters circled and a Ukrainian air force jet flew so low over the scene the roar of its engines blew blossom from nearby fruit trees and set off car alarms.
But neither the helicopters nor the repeated passes of the fighter could do anything. Faced with a large crowd and reluctant to use force on civilians, the paratroopers had little choice but to park up and await instructions.
In stages, the isolated troops were persuaded first to remove the clips from their rifles, then to surrender the firing pins in their weapons, and finally to give up their ammunition, which was loaded into a separate truck.
Watch: Slavyansk still under pro-Russian control
By sunset, the unit had been disarmed and had no choice but to agree to retreat. "We've been taken prisoner by dirty means," a commander barked into his mobile phone. "I'm surrounded by 500 people, what do you want me to do?"
Lena, a local woman holding a banner demanding a referendum on the region's status, said: "They call us terrorists, and they have the guns and tanks."
A paratrooper, who said he was from the city of Dnipropetrovsk, said: "I came here to defend our people. We're just following orders. Nobody wants a war. We'll get on OK with these people as long as they don't try to take the vehicles or our weapons. That's our stuff."
As the situation on the ground deteriorated, the authorities in Kiev continued to denounce Russian action.
Ukrainian army troops set up a position at an airport in Kramatorsk, eastern Ukraine. Photo / AP
Arseniy Yatsenyuk, the acting prime minister, accused Moscow of trying to build a new Berlin Wall and demanded that the Kremlin halt its alleged support for the separatists. "There is only one directive for the Ukrainian foreign ministry - the Russian government has to immediately withdraw its commando groups, condemn the terrorists and demand they leave the installations," he said.
Kiev's interim government is still committed to four-party talks with Russia, the European Union and the United States in Geneva today.
Russia's key demand at the talks is for Ukraine to assume a federal system of government that would grant its eastern regions a much greater degree of autonomy.
Ukrainian leaders have said they are ready to consider devolving powers to the regions, but have denounced full federalisation as a path to Russian annexation by other means.
But yesterday's military debacle will make it even more difficult to resist such demands.
The people blockading the Ukrainian troops at Cholkino were united only in demanding a referendum on regional status. But they were hopelessly divided on the questions it should ask, backing everything from full unification with Russia, to independence or devolved status within Ukraine. "All those people over there love their country, But we're sick and tired of feeding the rest," said Viktor, a 39-year-old railway worker, watching the stand-off from the level crossing. "Give us federalisation so the money that is earned in our mines stays here, in our budget, and doesn't go to Kiev."
Vladimir, the gunman who claimed to be from Donetsk, said he was not sure which way he would vote. "The idea is that the Donbass region has a voice that is listened to,'' he added.
Conventional troops in Russian uniform have still not been sighted in eastern Ukraine, although the heavily armed gunmen controlling the centre of Slavyansk do not hide that they took part in the takeover of Crimea.
"Yes I'm from Crimea, and of course I took part in the operation to restore order there," said a man who appeared to be in command. "We've got about six guys from Crimea. The other guys are from Kharkhiv, Dnipropetrovsk, and other places."
But the men equipped with heavy machineguns, sniper rifles and rocket launchers appeared to be military professionals, and Ukrainian commanders have said they believe at least some of the gunmen are Russian soldiers.
Russian or not, they are clearly the only authority operating in this increasingly lawless part of Ukraine.
As the sun set, the surrounded, disarmed Ukrainian paratroopers found their promised exit blocked by protesters who were determined to keep them there. It was only when the masked men with their automatic weapons, arrived to impose order that they were finally allowed to drive off into the night.
