A food warehouse in the Black Sea port of Odesa was destroyed in a Russian missile attack on Monday but no civilians were killed, the Ukrainian military said.
The Operational Command "South" said Russian forces fired 14 missiles at southern Ukraine during a three-hour barrage "in impotent anger at the successes of our troops." Russia's military did not immediately comment on the reports.
Explosions rocked Odesa after the Russia-installed head of the Crimea region, annexed by Moscow in 2014, said Ukrainian forces had attacked drilling platforms owned by a Crimean oil and gas company in the Black Sea off Ukraine's southern coast.
Three people were wounded, and a search was under way for seven workers, he said in a post on the Telegram messaging app.
Russia's RIA Novosti news agency said the drilling platforms were located 71 km (44 miles) from Odesa.
Sievierodonetsk Mayor Oleksander Stryuk said Russian forces controlled about two-thirds of the key eastern city, including most residential areas, and Moscow kept throwing forces at the Ukrainians in an attempt to take over completely.
Britain's Ministry of Defence said both Russia and Ukraine have continued heavy bombardment around Sievierodonetsk "with little change to the front line".
Analysts at the Institute for the Study of War think tank in Washington wrote: "Russian forces will likely be able to seize Sievierodonetsk in the coming weeks, but at the cost of concentrating most of their available forces in this small area."
Russian-backed separatist forces in Ukraine said they had taken the village of Toshkivka beside the main southern road toward Sievierodonetsk. Ukraine's Luhansk regional governor Serhiy Gaidai acknowledged that the Russian attack on Toshkivka "had a degree of success".
In southern Ukraine, Western weaponry had helped Ukrainian forces advance 10 km (6 miles) towards Russian-occupied Melitopol, its mayor said in a video posted on Telegram from outside the city.
The governor of Russia's Bryansk region said the border village of Suzemka had been shelled from northern Ukraine, and one person was wounded, and a power station was damaged.
Russia warned NATO member Lithuania that unless it quickly lifts a new ban on the transit of goods to Russia's Kaliningrad exclave on the Baltic Sea, then Moscow will take undisclosed measures to defend its national interests.
European Union foreign ministers will discuss ways to free millions of tonnes of grain stuck in Ukraine due to Russia's Black Sea port blockade at a meeting in Luxembourg on Monday.
Several EU countries are pushing to start work on a new package of sanctions against Russia and Belarus for the invasion of Ukraine and also want to grant more military support to Kyiv, according to diplomats and a draft document.
Europe's biggest Russian gas buyers are racing to find alternative fuel supplies and even looking at burning more coal to cope with reduced gas flows from Russia that threaten an energy crisis in winter if stores are not refilled.
