Rubble and shattered glass litter the floor. Water fills the corridors. Smoke and panic fill the air. In the living room a pinboard filled with photos of a smiling teenage girl and her friends hangs askew. Outside, that same girl, Ana, lies face down in the dirt of the courtyard, clothes seeped in dried blood. Next to her are the lifeless bodies of her sister and their parents.

“I will kill those Nazis. I will rip their throats out,” wails a distressed Yuri, who blames the Ukrainian army for the Grad attack that killed the family in the Petrovskiy suburb of rebel-held Donetsk, a city of 1 million. “Why you? What did you do to them?” he sobs, cradling his ex-wife’s body against his blood-stained cheek.

The family of four were killed and their house destroyed after being directly hit by grad rockets in the Petrovskiy suburb of Donetsk.

In the front garden, the dead family’s shell-shocked neighbor, Marina, shows VICE News the crater where an explosive hit. “We only just made it to the basement in time,” she says, gently trying to steer Yuri away from the scene.

The stories of death and explosions, of retreating to basements, are repeated across the Donbas region, where tens of thousands of civilians are caught in the crossfire of fierce fighting between pro-Russian rebels and Ukrainian forces.

In a suburb on the western outskirts of Donetsk, 70-year-old Valentina and her 17-year-old grandson, Alexey, blink as bright sunlight pours through the opened basement door. The duo hasrefused to come out of the darkness since mortars came crashing down on their village at 5AM, smashing through roofs and sending deadly shrapnel flying.

One landed in their frontyard, another destroyed a nearby children’s playground, a third ripped through the wall next to sleeping Alexy’s bed. “It is a miracle we’re still alive,” says Valentina. “We don’t know who is firing. We just know they hit our house,” she adds softly. Wide-eyed Alexy sits in silence; he can’t seem to find any words.

Pensioner Valentina and her grandson Alexy haven’t left the basement since 5AM this morning when mortars hit their family house.

A Human Right’s Watch report, published Friday, confirmed at least 16 civilians, including two children, were killed in a series of Grad attacks launched from Ukrainian-held territory into rebel-controlled Donetsk and its suburbs between July 12 and July 21 alone.

“Our investigation is by no means comprehensive," Ole Solvang, author of the report, told VICE News. "This figure refers to only a small number of reported attacks on populated areas in Ukraine."

Both sides have used heavy artillery in the conflict — including Grad rockets and mortars that cannot be properly targeted — but the trail of evidence in the cases examined by HRW leads back to the Ukrainian forces. “In all four cases, the angle and shape of the craters, and the fact that they were on the side of buildings facing the front line, strongly suggests that the rockets came from the direction of Ukrainian government forces or pro-Kiev armed groups. The attacks’ proximity to the front line also makes it unlikely, and in some cases impossible, that insurgent forces were responsible for the attacks,” reads the report.

"If these kind of attacks are repeated, if the Ukrainian government or separatists continue to carry out these kind of attacks knowing that there are civilians there, and they are dying, then this can constitute a war crime under international humanitarian law," he added.

In large swaths of the region there is now such fierce fighting that it is simply impossible to get accurate data on the number of wounded and killed.

At least 20 civilians have been killed in two misfired air strikes in the past month. In Snizhne, a small city close to the Russian border, 11 civilians were killed and eight seriously wounded after a Ukrainian fighter jet aiming for a rebel base dropped its load of bombs prematurely, hitting several residential apartment blocks.

A two miles stretch of road on the edge of Luhansk city center has been devastated by heavy shelling. Cars, shops, offices, and residential blocks have all been hit.

Last week in Luhansk, a neighboring oblast to Donetsk that is also under rebel control, a further 44 civilians were killed in two days alone, the local Red Cross branch told VICE News by telephone from its office basement where they had been holed up since morning under heavy shelling. “We are under fire and we can’t leave the building, there's no way out,” said a panicked-sounding Olga Tikhanova, chair of the Luhansk branch of the international NGO.

At least 230,000 people have fled the region, according to the latest estimated figures from the UN.

Luhansk, with a population of 450,000, has become the epicenter of fighting since the fall of the rebels’ heartland Sloviansk, after which Ukraine’s new president, Petro Poroshenko, announced a new phase of the Kiev-backed anti-terrorism operation aimed at “liberating” the two largest cities in the country’s east — Donetsk and Luhansk — from the rebels' control.

Those stuck inside can do little more than hope and wait. Roads in and out of the city have now become nearly impassable due to heavy shelling. Several suburbs are without electricity, and running water is only available “sporadically” in the center. “We are totally besieged, this place is like living hell,” local businessman Andrei Nedoves told VICE News by telephone from the besieged city.

A multi-rocket launch system six miles south of Donetsk in convoy of one hundred plus Ukrainian military vehicles including tanks and armored personnel carriers.

Last week a VICE News reporter witnessed multiple mortar hits across a two-mile stretch in the area surrounding the local bus station. Several buildings, including residential blocks, shops, and offices, were hit during the assault, which also pulled down electricity cables. Since then the situation has gotten much worse, says Nedoves. “Nowhere is safe anymore. They [the Ukrainians] are hitting everywhere. There is nowhere to hide”.

But, despite the overwhelming evidence to the contrary, the Ukrainian government has denied using Grad rockets and other heavy artillery areas in populated areas.

Oleksiy Melnyk, co-director of the Foreign Relations and International Security Program at the Kiev-based Razumkov Centre, told VICE News that the Russian researchers at HRW should be careful “of making generalizations from conversations with a few locals.”

“I’m not saying the Ukrainian soldiers are angels, but we have to remember this is not a simple narrative of good and bad. After the Yugoslav wars, it emerged that both sides were responsible for the shelling that killed civilians, so we have to wait and see,” he said, parroting the official line of Kiev that the rebel forces are behind the deadly attacks.

Melnyk, however, conceded the possibility that “Ukrainian forces have fired into civilian areas cannot be entirely ruled out.”

Ukrainian fighter without insignia six miles south of Donetsk arrived in a convoy of more than one hundred military vehicles including tanks and multi-rocket launch systems. "We are patriots here to fight the terrorists," he tells VICE News.

There are also serious questions about the degree of control Kiev exercises over the forces battling the rebels in the east, as well as their level of military training.

Still reeling from revolution and with its army starved of investment for nearly a decade, the government's hopes of winning the Ukrainian conflict have rested on a ragtag crew of reservists and hastily formed quasi-legal volunteer battalions of "patriots" who fight along soldiers.

Ad-hoc fighting group such as the Azov Battalion — funded by the banking tycoon and governor of Dnipropetrovsk, Ihor Kolomoisky — are believed to be behind attacks such as the one in Mariupol where at least seven civilians were killed as panicked soldiers opened fire from armored personnel carriers (APCs) in city center.

“Kerch” a Commander of the Russian Orthodox Army, a rebel fighter unit, in their HQ in Donetsk.

The lack of fighting experience among those on both sides of the front line has led to a preference for war from a distance, chucking heavy artillery at one another, rather than engaging in direct combat.

The desperate rebels, pushed further and further back, are increasingly resorting to classic guerrilla warfare techniques and using residential areas to launch their assaults.

“They [the rebels] move around the city and fire from between the buildings. When the Ukrainians fire back the fighters have gone, but the civilians are still there,” says Nedoves. “We are caught in the middle of this living hell,” he added.

Last week in a public meeting in Donetsk, angry locals confronted one of the rebels' leaders, Pavel Gubarev, the so-called People's Governor, about the fighters building gun positions on top of their apartment buildings. "Why are they on my roof and not yours?" shouted one angry woman. "Where is your family? They've left. But I can't leave. Tell me… what am I meant to do?"

There is little they can do; neither side shows any side of backing down.

“If they enter the city [Donetsk] we will fight them in every street,” Aleksandr Verin, aka "Kerch," a senior commander of the rebel fighting unit known as the Russian Orthodox Army, tells VICE News. “What started here will [be] finished here.”

Follow Harriet Salem on Twitter: @HarrietSalem