Moscow escalated its attacks in Ukraine on Saturday, with President Volodymyr Zelensky denouncing a deadly strike on a blood transfusion centre as a "war crime."A separate strike struck a key factory, both attacks coming just hours after Kyiv hit a Russian tanker in the Kerch Strait.The attacks were the latest since Moscow exited a deal last month that had ensured Ukrainian grain exports despite the ongoing conflict.Russian forces struck the blood transfusion centre in the Kharkiv regionof northeast Ukraine, Zelensky said, adding that "dead and wounded are reported."A "guided air bomb" hit the centre in Kupiansk, a city a few dozen kilometres from the Russian border, said Zelensky."Rescuers are extinguishing the fire," he wrote on social media, adding: "This war crime alone says everything about Russian aggression."The strike came shortly after Zelensky said Russian missiles had hit a facility of the Ukrainian aeronautics group Motor Sich, a maker of plane and helicopter engines and other components.It is one of several companies requisitioned by the government since Moscow's invasion.Motor Sich's headquarters are in the partially Russian-controlled region of Zaporizhzhia in southeast Ukraine.It was unclear if the Russian strikes had hit the Motor Sich headquarters.In his evening address, Zelensky remained defiant, insisting that "no matter how many such Russian attacks there are, they will still do nothing for the enemy."Attack on fuel tankerEarlier Saturday, Ukraine claimed it "blew up" a Russian tanker, the SIG, that was transporting fuel for Russian troops, a Ukrainian security source told AFP.The tanker was hit at around 11:20 pm on Friday south of the Kerch Strait,Russia's Federal Agency for Sea and Inland Water Transport said.The ship was holed at the waterline in the area of the engine room but was still afloat, the agency said.In a video obtained by AFP purporting to show the attack, a vessel is seen approaching a large ship before the connection cuts off.The Ukrainian source said the "successful special operation," which involved a naval drone and explosives, was carried out jointly with the navy in Ukrainian territorial waters.The SIG oil and chemical tanker is under United States sanctions for supplying jet fuel to Russian forces in Syria, who are supporting President Bashar al-Assad.Crimea focusThe Russian foreign ministry condemned the attack on a "civilian vessel," adding that the crew had not been injured.Traffic on a key bridge across the Kerch Strait linking the Moscow-annexed Crimea peninsula toRussia's mainland resumed early on Saturday after a three-hour halt, according to the Russian highways information centre's Telegram channel.Crimea has been disrupted by several strikes throughout the war but it has seen more frequent attacks in recent weeks.Russian forces on Saturday downed a drone over the sea near Sevastopol, city governor MikhailRazvozhayev said.Tensions have risen on the Black Sea overall sinceRussiapulled out of the agreement protecting grain exports via the shipping hub during the conflict.On Friday, Ukraine struck the Olenegorsky Gornyak vessel at the Novorossiysk base in southernRussia, a Ukrainian security source told AFP, "to show that Ukraine can attack any Russian warship in that zone."Russiasaid it had repelled the attempted attack.Frontline fightingOn the front line,Russiasaid Saturday it had captured the settlement of Novoselivske in northeastern Ukraine, where Kyiv said it was confronted with a growing number of attacks.Footage from the Russian army showed Novoselivske completely destroyed, with white smoke billowing over crumbling buildings.Ukrainian army spokeswoman Ganna Malyar said Friday that Russian troops were aiming to draw Ukrainian resources to the east, as Ukraine pursues its counter-offensive in the south.Ukraine began a fresh attempt in June to push back Russian troops but it has made only modest progress, its forces contending with well-entrenched Russian positions built up over several months.With both sides focused on winning on the battlefield, any chance to secure peace looks thin.Saudi Arabia is nevertheless hosting talks on the war with representatives from nearly 40 countries including China, India and South Africa but notRussia.The talks concluded Saturday and as expected, no final declaration was released.But a European source said there had been agreement that respect for Ukraine's "territorial integrity and sovereignty" should be "at the heart of any peace settlement."