Civilians including women and children remain trapped inside Ukraine's besieged city of Mariupol and a prolonged ceasefire is needed to ensure their evacuation as Russia presses its assault, Ukrainian President Volodymyr Zelenskiy said on Thursday.
After failing to capture the capital Kyiv in the early weeks of a war that has killed thousands and flattened cities, Russia has accelerated attacks on Ukraine's east and south.
Pavlo Kyrylenko, governor of the eastern region of Donetsk, said at least 25 civilians were wounded as Russian forces shelled Kramatorsk, and town some 180 kilometres (112 miles) west of Luhansk.
Moscow declared victory over Mariupol on April 21 after weeks of siege and shelling, but fierce resistance by Ukrainian forces holed up in the Azovstal steelworks has prevented Russia completely overrunning the city.
Mariupol is a major Russian target as the city is key to Moscow's efforts to cut Ukraine off from the Black Sea - vital for grain and metals exports - and link Russian-controlled territory.
The United Nations and Red Cross evacuated hundreds of people from Mariupol and other areas this week. But some 200 civilians, as well as Ukrainian fighters, are still holed up in a network of underground bunkers in the Azovstal plant, Ukrainian officials say.
Russia vowed to pause military activity at Azovstal during Thursday daytime and the following two days to allow civilians to get out. In an early morning address, Zelenskiy said Ukraine stood ready to ensure a ceasefire in Mariupol.
"It will take time simply to lift people out of those basements, out of those underground shelters. In the present conditions, we cannot use heavy equipment to clear the rubble away. It all has to be done by hand," Zelenskiy said.
Ukrainian fighters inside Azovstal are fighting "difficult, bloody battles" against Russian troops, Denis Prokopenko, a commander with Ukraine's Azov regiment, said late on Wednesday. A Ukrainian parliamentarian said Russian forces were inside the plant.
Over 300 civilians were evacuated on Wednesday from Mariupol and other areas in southern Ukraine as part of a joint U.N.-Red Cross operation, U.N. humanitarian coordinator for Ukraine Osnat Lubrani said.
It was not clear if further U.N. evacuations were planned. Tetyana Trotsak, a Ukrainian evacuee who was among dozens who reached a Ukraine-controlled town this week, voiced fear for those still trapped inside the steel plant.
"God forbid more shells hit near the bunkers where the civilians are," Trotsak said.
More than 5 million Ukrainians have fled abroad since Russian President Vladimir Putin Russia launched the invasion on Feb. 24.
Russia calls its actions in Ukraine a "special operation" to disarm Ukraine and protect it from fascists. Ukraine and the West say the fascist allegation is baseless and that the war is an unprovoked act of aggression.
As Western military aid for Ukraine pours into the country, the United States has also provided crucial intelligence that has helped Ukrainian forces kill Russian generals, the New York Times reported on Wednesday.
Washington has provided to Ukraine details on the location of Russia's mobile military headquarters, allowing Ukrainian forces to strike those targets, the newspaper said, citing senior U.S. officials.
The Pentagon and the White House did not immediately respond to Reuters' requests for comment on the report.
Ukrainian officials said they have killed about 12 Russian generals on the battlefield, according to the New York Times.
Ukraine's military said on Thursday its forces had repelled 11 Russian attacks, downed four Russian aircraft and destroyed over a dozen Russian military vehicles, including tanks.
Russian missile strikes in recent days have included railway stations in an attempt to interdict Western arms transfers.
The United States and its European allies have placed sweeping sanctions on Moscow over the invasion and provided Ukraine with billions of dollars worth of aid, including weapons that Kyiv says have led to heavy Russian losses.
Piling pressure on Russia's already battered $1.8 trillion economy, the European Union on Wednesday proposed phasing out imports of Russian crude oil within six months and refined products by the end of this year.
"Putin must pay a price, a high price, for his brutal aggression," European Commission chief Ursula von der Leyen told applauding EU lawmakers in Strasbourg.
The plan, if agreed by all 27 EU governments, would follow U.S. and British oil bans and be a watershed for the world's largest trading bloc, which remains dependent on Russian energy and must find alternative supplies.
A source said EU envoys could reach a deal on Thursday or later this week on the plan, which also targets Russia's top bank, its broadcasters, and hundreds of individuals.
The Kremlin said Russia was weighing various responses to the EU plan, adding that the measures would be costly for European citizens.