Ukraine's rebel movement was plunged into crisis on Thursday, when pro-Russian fighters backed by armoured personnel carriers seized the movement's headquarters in Donetsk and destroyed the barricades protecting it.
The surprise move by a group called the Vostok Battalion, a heavily armed rebel unit that has been involved in fighting against the Ukrainian army, sparked speculation about an internal coup within the fractious rebel movement.
There was also speculation that the move could have been an attempt by the leadership to purge undesirable elements with the Donetsk Peoples' Republic.
Key rebel leaders, who were not in the building when the fighters arrived, insisted they were still in control and that they had even ordered the operation.
"This is a police action directed against looters," a rebel source close to Alexander Borodai, the prime minister of the self-declared republic, said on Thursday afternoon.
"There is no coup. Everything is under control."
Gunmen from the battalion, which includes fighters from mainland Russia as well as Ukrainian-born volunteers, said they had acted out of disgust at the looting of a supermarket following the battle for Donetsk airport on Monday.
"We're on the same side, we're never going back to Ukraine. We're just against lawlessness and theft," said one fighter as he picked through the chaos left behind by the building's occupiers.
The 11-story regional administration building has been the headquarters of the Donetsk rebel movement since it was stormed and occupied by pro-Russian activists on April 6, sparking the uprising that led to the current conflict in the region.
Since then it has been used variously as the 'republic's' government headquarters, a parliament, a hospital, a command centre, and most notoriously as a prison.
Thursday's raid finally put an end to that occupation, with Vostok Battalion fighters evicting hundreds of pro-Russian activists from the building before bringing in bulldozers to destroy the barricades built to protect it against the police.
In one office on the sixth floor a fridge was stocked with huge cheeses and sausages bearing the logo of the Metro supermarket, a superstore close to the airport that was reportedly raided by well-organised looters after Monday's battle brought life in the district to a standstill.
In other offices, fighters found vast quantities of cigarettes, soft drinks, and shops own-brand socks and underwear stacked on desks and in wardrobes.
"We were starving on the battle field for two days," said a masked fighter, as he tested the ripeness of several mangos looted from the fruit and vegetable department that were scattered on a desk in a sixth floor office.
But looting - of which there was plenty of evidence - appears only to have been a pretext for a purge designed to assert control over the fractious rebel movement, eliminate autonomous groups, and possibly reverse a breakdown of law and order that has created increasing resentment amongst the public.
Denis Pushilin, the speaker of the republic's parliament, said the operation was aimed at "dishonest people" guilty of "criminal activity against the republic."
Access to the building had previously been tightly controlled, and the raid provided a rare opportunity to glimpse the chaotic mechanics of the pro-Russian counter revolution.
Offices were stacked with used ashtrays, discarded food and mattresses.
On the tenth floor several offices had been marked with the initials of the NKVD – Josef Stalin's feared secret police force, which the 'republic' appears to have attempted to revive.
The purge came as republican leaders dropped all pretence of Russian involvement in the uprising, with rebel leaders announcing the repatriation of dozens of bodies of Russian fighters killed in Monday's battle at the airport.
Lorries carrying the bodies of 33 Russian citizens, who were amongst dozens of rebels killed, left Donetsk for Russia on Thursday evening.
Casualties from Monday's fighting were so heavy that fighters had to take over a refrigeration facility at a local factory when the main city morgue overflowed.
The bodies of six fighters were laid in coffins waiting to be loaded on to the huge articulated refrigerator lorry that would carry them to the Russian border when The Daily Telegraph was granted access to the facility on Thursday.
Workers used painted a huge red cross and the number "200" – Soviet-era military code for dead bodies in transit – on the roof and sides of the lorry, in a bid to ward off attacks by Ukrainian aircraft.
The convoy, escorted by police, planned to carry the bodies to Rostov-on-Don, where they would be dispatched to families across Russia, rebel spokesmen organising the convoy said.
Rebel leaders say the Russian fighters were all volunteers, not members of the regular Russian armed forces.
They reiterated the hope that President Vladimir Putin would finally send troops to assist them.
The open admission of the presence of foreign fighters marks a remarkable change of tune from the separatist leadership, which previously maintained that its forces were entirely made up of locals.
While Donetsk was relatively calm on Thursday, fighting continued around the rebel stronghold of Slavyansk.
In a serious loss for the Ukrainians, 14 servicemen including a general were killed when rebels downed a helicopter near the city.
Olexander Turchynov, Ukraine's acting president told parliament rebels used a portable air defence missile to bring the down the helicopter and said Gen Volodymyr Kulchitsky was among the dead.
A separatist spokesman had earlier told Russian news agencies that the militants had downed a Ukrainian army helicopter in a fierce battle on the southern outskirts of the rebel-controlled city.
The unnamed spokesman said that "as a result of active military activities, several houses belonging to civilians caught fire".
The death toll is one of the highest suffered by Ukrainian forces since the separatist insurgency first erupted in eastern Ukraine in early April.
Source: The Telegraph