Russian attacks have destroyed an oil refinery in the central Poltava region and struck "critical infrastructure", most likely oil facilities, near the port city of Odesa, local officials said on Sunday.
Russian forces have attacked Odesa, the main base for Ukraine's navy, alongside other Ukrainian Black Sea ports such as Mariupol and Mykolaiv. If taken, it would give Russia a land corridor from Crimea to Transniestria, a Russian-speaking breakaway province of Moldova that hosts Russian troops.
Oil facilities have been a focus of attacks.
Kremenchuk, 250 km (150 miles) southeast of Kyiv along the Dnipro river, had Ukraine's only fully functioning oil refinery.
Dmytro Lunin, governor of the Poltava region, said on television that the refinery had been destroyed in a rocket attack on Saturday.
"The fire at the refinery has been extinguished but the facility has been completely destroyed and can no longer function," he said.
Reuters could not independently confirm the refinery's destruction. The plant processed 3.2 million tonnes of oil last year and its loss could prove a blow to Ukraine's defence effort.
Several rockets also hit Mykolaiv, an interior ministry aide said.
Earlier, Russia's defence ministry said its missiles had destroyed an oil refinery and three fuel storage facilities near Odesa. It said they had been used by Ukraine to supply its troops near Mykolaiv.
Vladyslav Nazarov, an officer of Ukraine's Southern Operational Command, said on Telegram that there had been a missile attack on "critical infrastructure". Two columns of thick, black smoke could be seen rising into a grey sky before spreading out over the city.
"All relevant systems and structures are working ... No casualties reported," Nazarov added. Reuters could not confirm details of the attack.
Odesa Mayor Gennadiy Trukhanov said on television the situation was "under control", adding: "Homes, civilian infrastructure, roofs have suffered damage."
Vika, a local resident who declined to give her surname, said her family had woken up to powerful explosions near their home.
"There was smoke, the children were in a panic, the windows were blown in ... it was terrifying," she said.
Russia denies attacking civilians.
Russian forces invaded Ukraine on Feb. 24 in what the Kremlin calls a "special military operation" to demilitarise and "denazify" its neighbour.
Ukraine and the Western countries supporting it reject that as a baseless pretext for a war of aggression.
(Reporting by Issam Abdallah and Pavel Polityuk; Writing by Lidia Kelly in Melbourne, Elizabeth Piper in Lviv and Sujata Rao in London; Editing by Stephen Coates, Frances Kerry and Kevin Liffey)
