DONETSK, Ukraine - Glass and fallen branches crunched underfoot on a central street in east Ukraine’s Donetsk as rebel fighters fidgeted with their guns and panicked residents ran in and out of doorways.Nearby a body lay sprawled on the pavement - one of at least two people killed when shelling on Thursday tore through a downtown avenue and elite housing complex in the besieged separatist stronghold.The heavy daytime bombardment hit right in the heart of the industrial city, smashing into apartments and shattering shop fronts around. A grey-rendered pre-war residential building on a central street had windows blown out and balconies damaged. There were impact holes on two sides “I came and saw it. My house is nowhere any more,” said Irina, whose family had lived there since before the wartime Nazi occupation of Ukraine. “It’s good my daughter and my granddaughter have gone away. Thank goodness, my neighbours are alive.”The main military commander of pro-Russian rebels battling government forces in east Ukraine, Igor Strelkov, quit his post Thursday, the separatist leadership said. The insurgent authorities “approved the resignation” of Strelkov, who is Russian, from his post as defence minister of the self-proclaimed Donetsk People’s Republic “in connection with his transfer to another job,” the rebels said in a statement on their website.The fierce firing forced staff at the rebels’ headquarters, a Soviet government office block occupied since April, to rush into its bomb shelter. “It’s because of the shelling,” said a spokeswoman for the rebels.Regional and city authorities, which are still operating to a degree despite the insurgents’ presence, gave initial figures that two died and seven were injured in the shelling incidents.A gun-toting rebel in a bandanna and sunglasses, who declined to give his name, said the mortar fire cut down people in the street. “A person was just walking along and died. There’s a person lying in the yard too. There’s a minimum of two dead,” he said.He blamed the Ukrainian troops surrounding the city for the attack. “They want to scare peaceful people and make them go away,” he said. On a nearby street, windows were smashed in a library while a nearby shopping centre and office complex were also damaged.Shelling also hit an elite housing complex on Kalinin Street, a short ride from the centre. It has spacious houses painted in different colours and a deserted air.A shell had ripped open the third floor of a large apartment block to reveal the room inside. Windows were smashed on all five floors.An adjacent row of large townhouses had smashed windows. On the opposite side of the road firefighters battled to douse flames ravaging a private home.An elderly woman in a flowery housecoat living on the road, Nadezhda, said she counted herself lucky. “My windows are smashed, I don’t think that’s too bad,” she said. “I saw nothing but I heard it. I was in the cellar and everything shook. When I came out, it was horrible.”A local resident, Marina, said she had come to check on the request of one of the house’s owners. She said that South American football stars Luiz Adriano and Douglas Costa from the local Shakhtar Donetsk team had lived in two of the townhouses in the complex. The team has long since left the conflict-torn city.Marina said she was convinced that separatist rebels were behind the attack, believing them to be firing from a former mine nearby. “It is terrorists shooting, not the Ukrainian army,” she said. “They shoot at peaceful people.”Meanwhile, a massive Russian “humanitarian” convoy closed in on Ukraine’s border Thursday despite doubts over whether the trucks would be allowed across, and as deadly fighting rocked rebel-held strongholds.The nearly 300 vehicles headed towards southeastern Ukraine, even as intense shelling there in the insurgent bastions of Donetsk and Lugansk - where the trucks appear headed - sharply increased the death toll from fighting.Health authorities in Donetsk, the centre of which was under heavy shelling by the army, said 74 people were killed in fighting over the past three days. Government forces at the same time reported nine dead and 18 injured among its troops, following four months of fighting that have left over 2,000 dead and many residents without power, running water and with dwindling food supplies. Meanwhile, Ukraine dispatched aid convoys of its own from three cities to a government-held eastern town as it tried to race Moscow to hand out much-needed aid to residents in the blighted region.The Russian convoy, a three-kilometre (two-mile) file of white-tarpaulin-covered lorries, reached the Rostov region in southwestern Russia Thursday, a spokesman for the Russian emergencies ministry in Moscow told AFP. It was not immediately clear when the trucks would arrive at the border or whether Ukrainian officials would allow them to pass.The convoy had earlier headed for government-controlled territory in the region of Kharkiv further west, with Kiev insisting only the aid and not the lorries would be allowed to cross the border.On Wednesday however, President Petro Poroshenko’s office suggested the aid could travel more directly to the stricken east and be allowed into Ukraine under certain conditions.Fears have mounted that the lorries rumbling toward the border could spark an escalation in a conflict that has already brought ties between Russia and the West to their lowest point since the Cold War.Ukraine and the West have warned that Moscow’s operation could be a “Trojan horse” bringing military help to pro-Russian insurgents, who have been losing ground to government troops in the east.Moscow denies the allegations, insisting the aid operation was coordinated with the International Committee of the Red Cross (ICRC), and that no military escort accompanied the lorries. As the convoy moved nearer to the Ukrainian border, Donetsk and Lugansk - the rebels’ two biggest strongholds - came under renewed fire on Thursday.Heavy shelling smashed into the centre of Donetsk, once a bustling city of one million. Health authorities said 74 were killed and 116 wounded over the past three days.