Graham Stack in Lugansk -

Ukraine's struggle against Russian-backed rebels in East Ukraine has shifted to the border region with Russia, to cut off the flow of supplies and men to the rebels. Shellfire rained on the outer districts of the large border town of Lugansk on July 14-16 as rebels dug in.

"This is a genocide against the people of east and south Ukraine," Anatoly Voevidko, a 63-year-old pensioner, standing in a lane of ruined cottages in north Lugansk, tells bne. Shelling struck the three houses on Kuibyshev street in the night of July 15 and again in the daytime of July 16. Because this district is one of garden allotments with low population density, only two people were injured in the attacks, with both out of danger, according to the city's police department.

Others may not have been so lucky. bne counted at least five other shell hits in the early evening, with the crash of explosion followed by plumes of smoke. Shells also hit buildings and streets in southern districts of the town of Lugansk on July 15-16. Eerily silent ambulances and fire engines raced to the impact scenes without sirens, due to the near-complete absence of traffic on the roads, with most of the population having left the city or hiding at home. According to the Lugansk police department, at least seven individuals died as a result of shelling on July 15. There were as yet no official figures for July 16.

Who is doing the shelling? "It is bad people, the Ukrainian forces," said Sergei, a member of the separatist's self-styled State Security Committee (KGB), who declined to give his last name.

The pensioner Voevidko also had no doubt that the Ukrainian army, encamped just kilometres outside Lugansk to the north, is responsible for the shelling. "It is open war against civilians. There is no possible strategic significance to this area," he protested.

However, bne also saw and heard in the dusk what appeared to be the firing of a volley of rockets out of north Lugansk, apparently by one of the feared Soviet-built "Grad" truck-borne multiple rocket launchers that are in rebel hands. Pro-Kyiv activists and analysts widely claim that rebels have placed their weaponry in built-up areas to use civilians as a "human shield" against Ukrainian counter-fire. Some also claim that the rebels are themselves firing mortars on parts of the city, to whip up local hatred of Kyiv and increase international pressure on Kyiv to halt operations, although bne could not confirm this.

Border warfare

As the Ukrainian forces advance into the Donbass basin – an area covering three administrative provinces (oblasts) in the east of Ukraine – and towards the major cities of Donetsk and Lugansk, they are faced with the prospect of street-to-street fighting against the rebels, if they try to take back the towns. Given the restrictive terms of engagement laid down by Ukraine's "anti-terrorist operation," this would lead to high losses among the military, as well as inevitable civilian casualties.

This makes it crucial for Kyiv to first cut the rebels off from the Russian-Ukraine border in Lugansk region, across which is coming increasingly heavy weaponry – such as tanks and "Grad" units – and men capable of handling them, according to Kyiv. "The most intense fighting now is along the border… [Russian President Vladimir] Putin knows that if the rebels' land connection to Russia breaks, this will be the end of the conflict in Donbass," says Dmitry Timchuk, at Centre of Military-Political Research. "He will do anything to stop this."

Ukrainian forces on the Russian border in Lugansk are, however, coming under fire from the rebels in and around Lugansk, which is less than 30km from the nearest part of the border. Moreover, a video clip uploaded to a Russian social network profile on July 16 appears to show "Grad" rockets also being fired out of Russia across the border towards Ukrainian forces. The clip was later removed from the profile.

Attacks from the Russian side as well could yet turn the border region into a "canyon of death" for Ukraine's still raw and under-equipped troops: over 30 Ukrainian soldiers and border guards died July 11 under rebel "Grad" fire, in Zelenopillya, on the Russian border south of Lugansk.

Another focus of fighting in Lugansk is the city's airport, which is held by Ukrainian army units but came under intense shelling on July 16. If the rebels were to seize the airport, it could provide a crucial bridgehead for Russia to step up its support for the fighters, in addition to the land border. "And that would be an entirely different level of war," says Serhiy Garmash, editor at ostro.org and expert for the Donbass region.