On Friday night, a Russian tanker in the Black Sea was hit by a drone, as ITV News' Callum Watkinson reports
Deaths and injuries have been reported after Russia bombed a blood transfusion centre in Ukraine, President Volodomyr Zelenskyy has said after his own nation was blamed for attacking a Russian tanker around 24 hours earlier.
On Saturday night, the Ukrainian leader tweeted a picture of a badly damaged building, lit from inside by a huge blaze. Emergency services appeared to be in attendance.
Mr Zelenskyy wrote: "Russia's guided air bomb against a blood transfusion center in Ukraine. This evening, Kupiansk community in Kharkiv region. Dead and wounded are reported. My condolences! Our rescuers are extinguishing the fire.
"This war crime alone says everything about Russian aggression. Beasts that destroy everything that simply allows to live. Defeating terrorists is a matter of honor for everyone who values life."
Russia has not confirmed or denied launching such an attack and ITV News could not immediately verify Mr Zelenskyy's claim.
On Friday night, Ukrainian drones had hit a Russian tanker in the Black Sea near Crimea, according to Russian officials and video circulating on social media.
The strike was the second sea attack involving drones in one day, after Ukraine struck a major Russian port earlier on Friday in an attack that underlined Kyiv’s growing naval capabilities as the Black Sea becomes an increasingly important battleground in the war.
Moscow strongly condemned what it saw as a Ukrainian “terrorist attack” on a civilian vessel in the Kerch Strait.
Russian Foreign Ministry spokeswoman Maria Zakharova said: “There can be no justification for such barbaric actions, they will not go unanswered and their authors and perpetrators will inevitably be punished.”
The attacks follow Russian strikes on Ukrainian ports after Moscow nearly three weeks ago withdrew from a key grain-export agreement that allowed Ukraine to sell millions of tons of grain on world markets.
“The Sig tanker...suffered a hole in the engine room near the waterline on the starboard side, presumably as a result of a sea drone attack,” Russia’s Federal Agency for Marine and River Transport wrote on Telegram, adding that there were no casualties among the 11 crew members.
Vladimir Rogov, a Kremlin-installed official in Ukraine’s partially occupied southern Zaporizhzhia region, said several members of the ship’s crew were wounded because of broken glass.
An official with Ukraine's Security Service confirmed to news agency The Associated Press that the service was behind the attack on the tanker, which was transporting fuel for Russian forces.
A sea drone, filled with 450 kilograms (992 pounds) of TNT, was used for the attack, added the official who spoke on condition of anonymity because he was not authorised to give official statements.
Vasyl Malyuk, who leads Ukraine’s Security Service, said that “such special operations are conducted in the territorial waters of Ukraine and are completely legal.
Any such explosions, he said, are “an absolutely logical and effective step with regard to the enemy.”
The attack briefly halted traffic on the Kerch Bridge, the 19-kilometre (12-mile) bridge linking Moscow-annexed Crimea to Russia, as well as ferry transport.
Tugboats were deployed to assist the tanker, which is under United States sanctions for helping provide jet fuel to Russian forces fighting in Syria, according to Russia’s Tass news agency.
Ukraine's earlier strike on Novorossiysk halted maritime traffic for a few hours and marked the first time a commercial Russian port has been targeted in the nearly 18-month-old conflict.
The port has a naval base, shipbuilding yards and an oil terminal, and is key for exports. It lies about 110 kilometres (about 60 miles) east of Crimea.
Want a quick and expert briefing on the biggest news stories? Listen to our latest podcasts to find out What You Need To Know.