'WHY didn't you say they were journalists?" barked the masked gunman at our translator.

Just moments earlier the car in which I was travelling with a Swedish colleague had been flagged down at a checkpoint manned by pro-Russian militants on the outskirts of Sloviansk.

The leader of the militants, a burly, aggressive man in camouflage fatigues and wearing a black ski mask, was evidently incensed that, having stopped us, our Ukrainian interpreter had not immediately declared that we were reporters.

For a few tense moments it seemed inevitable we would be prevented from travelling further or perhaps even detained, before the man brusquely waved us through the chicane of tyres, sandbags and barbed wire barricades.

Three more checkpoints lay ahead before we reached the centre of Sloviansk. The last of these was at a roundabout alongside the Seversky Donets River. It was in this river last week that the bodies of local politician, Volodymyr Rybak, and 19-year-old Kiev Polytechnic Institute student, Yuriy Popravko, were found dumped following torture and murder.

For the past few weeks the down-at-heel industrial town of Sloviansk has been at the heart of the insurgency that has pitched pro-separatist fighters against Ukrainian government forces.

Abductions, disappearances, torture, intimidation, paranoia and the rule of the gun have become the order of the day here. So much so, that last week the Ukrainian government in Kiev appeared to have run out of patience with the militants who control the town. On Thursday Ukrainian commandos backed by armoured vehicles attacked a few checkpoints on the outskirts of Sloviansk, killing a number of separatists.

"We've decided to completely blockade the city to prevent reinforcements from coming in," said Sergei Pashinsky, Ukraine's chief of staff. "The goal is to blockade the terrorists and prevent any civilian casualties."

Nonetheless, casualties in the struggle for Sloviansk and other contested towns in eastern Ukraine continue to mount, albeit slowly for now.

Arriving in the town last week we left our car to walk into Sloviansk's main square. Warm weather had brought people on to the streets, many milling around the barricades constructed around the town's police station. A row of huge metal riot shields acts as a makeshift door in the barricade through which pass masked gunmen and youths with clubs.

A few hundred yards away in the main square sits the town hall, its entrance also heavily sandbagged and armed sentries keeping watch from the roof. Beneath a giant statue of Lenin the townsfolk congregate. Some watch over their playing children while nearby the ubiquitous masked men with Kalashnikovs patrol.

"It will only be better here when these people leave," insisted 17-year-old Valentin, a student, speaking of the "outsiders" he says have come to Sloviansk of late.

Asked if he meant Russians, his reply was unequivocal."This is a fairly small community, we notice when outsiders come, especially those carrying guns. Of course they are Russians."

I asked if he had talked with any of them. "It's difficult to have a conversation with men who carry weapons," Velantin replied with a wry smile, his two young female friends, Anya and Nastya nodding in agreement alongside him.

Walking around Sloviansk it is impossible not to notice the unwelcoming looks some locals give other outsiders like western journalists. Though many locals are said to have little truck with the separatists, the reality is that this has always been a one-party town where criminal gangs with strong pro-Moscow leanings have often ruled.

For many, Viktor Yanukovych is still their man. To some, the Moscow-backed Ukrainian president recently brought down by the uprising in Kiev is nothing short of a hero.

"When the fascists forced president Yanukovych out of Kiev, I decided to leave Russia and return here to help those who want him back," insisted a 31-year-old man who would only give his name as Artyom.

Artyom was working in Vladivostok as an electrician but returned to Sloviansk as the separatist uprising gained momentum.

"I have had enough of the government in Kiev," Artyom went on. "Donetsk region works hard for all of Ukraine but we receive nothing in return, so I would now like to see it part of Russia - even if it means picking up an AK [rifle]."

Many pro-Russian separatists like Artyom readily refer to the interim government and its supporters as "fascists". That the Maidan uprising saw Ukrainian ultra-nationalist groups like the Right Sector take to the streets is well established, but they represent only a tiny minority of those who deposed Yanukovych.

That all in Kiev are fascists in the eyes of pro-Moscow separatists is a view reinforced by the Russian media to which Sloviansk locals almost exclusively listen.

TV and radio depict activists in the uprising as Nazis. Drawing such parallels helps fuel a nostalgia for the days of the Soviet Union - a key factor in the Kremlin's propaganda message.

Two hours south from Sloviansk, in the regional capital Donetsk, pro-Russian militants occupying the city hall have hoisted Soviet-era banners. From a battery of speakers the Red Army Choir bellows The Sacred War, a Second World War anthem that evokes strong emotion in Russians over a certain age and helps endorse a new-found nationalism in a younger generation of Russian speakers.

"Our huge country is rising

is rising for the deathly battle

Against the dark fascist force

Against their cursed hordes."

Time and again in Sloviansk, and in other areas where pro-Russian separatists hold sway, you hear another common refrain: "provocateurs" and "provocations".

At times, a near-paranoia grips the gunmen who control Sloviansk. Last week, just off the town's Karl Marx Street, where a cluster of armoured personnel carriers sit behind walls of sandbagged emplacements, the gunmen seemed particularly jumpy. "No, no," ordered one as he twisted the neck strap on my camera to ensure it faced at my chest.

Never keen to be photographed, there has been a heightened sensitivity among the ranks of these militants after the US State Department released images it claimed proves armed separatists in eastern Ukraine are actually Russian military or intelligence officers.

Masks have become de rigueur among these cadres and a leitmotif of the crisis on the streets.

These mask-wearing militants represent the latest face of Russia's tradition of "maskirovka", which literally means "disguise" but which has long been used in a broader sense to mean any military tactic that incorporates concealment, deception or disinformation.

According to some military analysts, Russia's flair for maskirovka has flourished under president Putin, a former KGB officer whose closest advisers are still mostly from the ranks of Soviet intelligence.

A New Tork Times journalist recently told how one masked gunmen in Sloviansk's main square responded when he was asked where he was from. "New Russia," replied the gunman, using an old czarist-era term recently revived by Russia's president Putin in reference to a large section of eastern and southern Ukraine.

Given such attitudes, it's hardly surprising that many western reporters have increasingly been viewed by the pro-Moscow militants as "spies" or "provocateurs" hell-bent on furthering the goals of the "fascist" and "western supported" Kiev government of destabilising these Russia-leaning regions.

Entering and leaving Sloviansk, its gunmen regularly demand that western reporters produce passports and other identifying documents. Some, like VICE News journalist Simon Ostrovsky, have been arrested and detained, as have a number of Ukrainian journalists. Released last week after being held for four days, Ostrovsky described his experience and that of other prisoners.

"After spending hours alone on the floor of a damp cell with my hands tied behind my back and a hat pulled over my eyes, I was led into a room where I was accused of working for the CIA, FBI, and Right Sector, the Ukrainian ultra-nationalist group," he wrote.

"Some were journalists, some were drunks, and others were Ukrainian activists stupid or brave enough to visit what's become a stronghold for Russian nationalists within Ukraine."

As I write, pro-Russian separatists are currently holding eight international observers from the Organisation for Security and Cooperation in Europe (OSCE) who were kidnapped around Sloviansk. True to form the separatists said they suspected the observers of spying. The Ukrainian government insists they are being used as human shields in Sloviansk.

"They were soldiers on our territory without our permission - of course they are prisoners," insists the self-styled mayor of Sloviansk, Vyacheslav Ponomaryov, who has warned of turning the town into another Stalingrad should Ukrainian forces attempt to retake the town. This of course is yet another reference to the Second World War fight against fascism when the Soviet Union heroically defended the Soviet city against the Nazis.

Bad as is the kidnapping of the OSCE monitors, it is Ukrainian civilians, of course, who are bearing the brunt of the violence and intimidation. Over the past week around Sloviansk there has been an escalation in separatists efforts to intimidate or eliminate the most outspoken Ukrainian advocates, with an increasing numbers of activists, journalists and officials being threatened, attacked, kidnapped, killed or disappeared.

All the early warning signs of the potential for a rise in human rights abuses were evident last week when the bodies of Volodymyr Rybak and Yuriy Popravko, an activist who had taken part in the Maidan protest in Kiev, were discovered tortured and murdered in the river.

On calling her son Yuriy's phone after his initial disappearance, his mother Yaroslava Popravko was told by whoever answered that he had died but that his phone was being kept to "locate friends."

Last Thursday, in a phone call from my young Ukrainian translator who had accompanied me into Sloviansk, I was told that a work associate of his girlfriend had disappeared somewhere around the town while en route to a business meeting. For the time being at least, it's hard to imagine anything other that gun law ruling Sloviansk's streets in the days and weeks ahead.

David Pratt was named feature of the writer this week