Russian forces fired rockets at the encircled steel works in Ukraine's Mariupol and smoke darkened the sky above the plant, where officials say 200 civilians are still trapped despite evacuations, while the EU prepared to sanction Russian oil.
Reuters images showed volleys of rockets fired from a Russian truck-mounted launcher on the outskirts of the Russian-occupied city of Mariupol.
The attack followed a UN-brokered ceasefire around the Soviet-era steel complex that allowed several groups of civilians to escape the last holdout of Ukrainian fighters in the southern port in recent days.
More civilians were trapped in bunkers and tunnels under the complex and some 100,000 remained in the rest of the city, mayor Vadym Boychenko said on Tuesday.
"You wake up in the morning and you cry. You cry in the evening. I don't know where to go at all," said Mariupol resident Tatyana Bushlanova, sitting by a blackened apartment block and talking over the sound of shells exploding nearby.
Mariupol is a major target for Russia as is seeks to cut Ukraine off from the Black Sea and connect Russian-controlled territory in the south and east.
Russia's offensive in eastern Ukraine, focused on the regions of Donetsk and Luhansk, killed at least three civilians in the city of Vuhledar, the Ukrainian president's office said. Ukraine's military said Russian forces were trying to take the frontline town of Rubizhne.
Russian bombardments since troops invaded Ukraine on February 24th have flattened cities, killed thousands of civilians and forced more than five million to flee the country.
The war shifted to the eastern provinces, parts of which were already held by Russian-backed separatists before Russian president Vladimir Putin launched the invasion, after Russia abandoned an assault on Kyiv at the end of March.
Its troops are trying to encircle a large Ukrainian force there, attacking from three directions with massive bombardment along the front, in what Moscow says is a special military operation to tackle nationalists it calls Nazis.
In response, Western allies of Ukraine have stepped up supplies of increasingly heavy weapons. Ukraine's first lady Olena Zelenska asked the West to maintain its support.
"Ukraine needs weapons so that Ukrainian refugees can return home and rebuild the economy. Therefore, we ask you not to stop, to accelerate the pace of heavy weapons provision," she told British morning television.
She said she had not seen Ukrainian president Volodymyr Zelenskiy since the start of the invasion.
EU sanctions
In Brussels, the European Commission is expected to finalise a sixth package of EU sanctions against Russia on Tuesday, including a possible embargo on buying Russian oil. In a major shift, Germany said it was prepared to back an immediate EU embargo on Russian oil.
The European Commission may spare Hungary and Slovakia from the embargo because of the two countries' dependence on Russian crude, two EU officials said on Monday.
Kyiv says Russia's energy exports to Europe, so far largely exempt from international sanctions, are funding the Kremlin war effort with millions of euros every day.
"This package should include clear steps to block Russia's revenues from energy resources," Mr Zelenskiy said in his nightly video address.
EU countries have paid more than €47 billion to Russia for gas and oil since it invaded Ukraine, according to research organisation the Centre for Research on Energy and Clean Air.
Ambassadors from EU countries will discuss the proposed oil sanctions when they meet on Wednesday.
Pope Francis said in an interview published on Tuesday that he had asked for a meeting in Moscow with Putin to try to stop the war but had not received a response.
The pope also told Italy's Corriere Della Sera newspaper that Patriarch Kirill of the Russian Orthodox Church, who has backed the war, "cannot become Putin's altar boy".
The pope told the newspaper that Hungarian Prime Minister Viktor Orban had told him Russia planned to end the war on May 9th, which Russia celebrates as 'Victory Day', marking Nazi Germany's surrender in 1945.
Russian foreign minister Sergei Lavrov said earlier this week that Moscow would not rush to meet that symbolic date.
Trail of destruction
Ukraine's second-biggest city, Kharkiv, was under bombardment, as it has been since the early days of the invasion, the Ukrainian military said on Tuesday.
Giving an early update on the battle front, Ukraine's general staff said its forces were defending the approach to Kharkiv from Izyum, a town on the Donets river, some 120km to the southeast, as the enemy left a trail of destruction in Luhansk province.
Some other areas of Donetsk were under constant fire and regional authorities were trying to evacuate civilians from frontline areas, the president's office said.
Reuters could not independently verify Ukraine's battlefield accounts.
Heavy clashes were taking place around Popasna, in Luhansk. Shelling was so intense it was not possible to collect bodies, regional governor Serhiy Gaidai said.
"I don't even want to speak about what's happening with the people living in Popasna, Rubizhne and Novotoshkivske right now. These cities simply don't exist anymore. They have completely destroyed them."
