More grim attacks on civilians by Vladimir Putin's Russian forces are expected as Ukraine continues to try and push forward its recent advance.
Putin pledged a "more serious" response by his military if the Ukrainian counteroffensive continues and claimed the main aim of the campaign is "the liberation of the entire territory of Donbas".
On Friday he added: "We are really quite restrained in our response to this for the time being. If the situation continues to develop in this way, the response will be more serious."
In its intelligence update for September 18, the Ministry of Defence (MoD) said that over the last seven days, Russia "has increased its targeting of civilian infrastructure even where it probably perceives no immediate military effect".
Overnight shelling is reported to have hit a hospital in the Black Sea port of Mykolaiv, according to regional governor Vitaliy Kim.
In Kharkiv, where Ukraine made major gains last week, three are believed to have died in a rocket attack and one victim was an 11-year-old girl.
The MoD added: "As it faces setbacks on the front lines, Russia has likely extended the locations it is prepared to strike in an attempt to directly undermine the morale of the Ukrainian people and government."
Putin's bombs have wreaked havoc on civilian life in Ukraine and The Office of the United Nations High Commissioner for Human Rights (OHCHR) has so far verified a total of 5,827 deaths as of September 11.
Of that total, 349 were children.
In liberated Izium, a mass grave was uncovered where the bodies of the dead show signs of torture and some have ropes tied around their necks and hands. An estimated 400 shallow graves were found.
The UN's refugee agency (UNHCR), meanwhile, believes a total of 13 million people have been forced to flee their homes to escape the invading Russian troops and their artillery shells.
Concerns remain that a continues Russian retreat could cause Putin to resort to even more vicious and irresponsible bombing tacts, even the possibility of tactical nuclear weapons.
In a preview for an upcoming episode of 60 Minutes on CBS news, US President Joe Biden warned against Russia employing such tactics.
Explaining that the US would be forced to act if nukes were used, Biden said: "Don't. Don't. Don't. You will change the face of war unlike anything since World War II.
"It'll be consequential [ Russia ] will become more of a pariah in the world than they ever have been. And depending on the extent of what they do will determine what response would occur."
It is unclear how likely the Ukrainian advance may continue in the coming days and the MoD report from September 17 expected a "stubborn" defence from Russia as they try to hold on to key areas.
Explaining, the MoD said Ukraine is continuing offensive operations in the northeast of the country and Russian troops have established a line of defence in the Luhansk Oblast town of Svatove.
"Russia likely sees maintaining control of this zone as important because it is transited by one of the few main resupply routes Russia still controls from the Belgorod region of Russia," said the defence ministry.
"This line sits along the border of Luhansk Oblast, part of the Donbas, which Russia aims to ‘liberate’ as one of its immediate war aims. Any substantial loss of territory in Luhansk will unambiguously undermine Russia’s strategy.
"Russia will likely attempt to conduct a stubborn defence of this area, but it is unclear whether Russia’s front line forces have sufficient reserves or adequate morale to withstand another concerted Ukrainian assault."
