ZAPORIZHZHIA. The European Union is expected to outline oil sanctions against Russia on Wednesday as its forces pounded targets in eastern Ukraine, unleashing rockets on a steel plant that is the last redoubt of resistance in the port city of Mariupol.

Scores of evacuees who managed to leave the city under UN and Red Cross auspices reached the relative safety of Ukraine-controlled Zaporizhzhia on Tuesday after cowering for weeks in bunkers beneath the sprawling Azovstal steel plant.

Weary-looking evacuees, including children and old people, clambered off buses after escaping the ruins of their home town in southeastern Ukraine where Russia now claims control.

"We had said goodbye to life. We didn't think anyone knew we were there," said Valentina Sytnykova, 70, who said she sheltered in the plant for two months with her son and 10-year-old granddaughter.

Russia is targeting Mariupol as it seeks to cut Ukraine off from the Black Sea and connect Russian-controlled territory in the south and east. Parts of the eastern regions of Donetsk and Luhansk were held by Russian-backed separatists before President Vladimir Putin launched the Feb 24 invasion.

More than 200 civilians remain in the plant, according to Mariupol Mayor Vadym Boichenko, with 100,000 civilians still in the city.

"Where am I to go? Let them blow me up here," a 67-year-old woman told Reuters in the city, as she boiled water on an open fire amid the rubble of a destroyed apartment block.

Pummelled by Western sanctions, Russia now faces new measures from the EU that would target its banks and oil industry - a major step for European countries that rely heavily on Russian energy.

European Commission President Ursula von der Leyen is expected to spell out the proposed new sanctions on Wednesday, including a ban on imports of Russian oil by the end of this year.

Russia showed no signs of backing down nearly 10 weeks into what it calls a "special military operation," a war that has killed thousands, destroyed cities and driven 5 million Ukrainians to flee abroad. Russia's own $1.8 trillion economy is heading for its biggest contraction since the years following the 1991 break-up of the Soviet Union.

Putin raised the economic stakes for Kyiv's Western backers by announcing plans to block exports of vital raw materials.

Russian forces have turned their heaviest firepower on Ukraine's east and south after failing to take Kyiv, the capital, in the opening weeks of the war.

But there were also new attacks in the west on Tuesday. The mayor of Lviv said Russian missile strikes had damaged electricity and water networks in the city near the Polish border, across which flow Western arms supplies for Ukraine's military.

Russian forces also struck six railway stations in the centre and west of the country, the head of Ukraine's railways, Olesksandr Kamyshin, said. There were no injuries to civilians, he added on Twitter.

In the east, Russian attacks in Donetsk on Tuesday killed 21 civilians and injured 27, regional Governor Pavlo Kyrylenko said.

Attacks and shelling also intensified in Luhansk, with the most difficult area being Popasna, where it was impossible to organise evacuations, regional Governor Serhiy Haida said.

"There are no safe cities in Luhansk region," he said on the Telegram messaging service.

In a daily update on the conflict zone, British military intelligence said Russia has deployed 22 battalion tactical groups near Ukraine's eastern city of Izium in an effort to advance along the northern axis of the Donbas region, and added that it was likely that Russian forces intended to capture the cities of Kramatorsk and Severodonetsk.

Reuters could not immediately verify the report.

Ukraine's general staff said its forces had repelled an attempted Russian advance through Dovgenke, about 108 km (67 miles) east of Kharkiv, Ukraine's second largest city.

In the south, Russia said it had struck a military airfield near the Black Sea port of Odesa with missiles, destroying drones, weapons and ammunition supplied by the West. Ukraine said three missiles targeted the Odesa region and all were intercepted.

Adding to Ukraine's concerns, neighbouring Belarus, a close ally of Russia, said on Wednesday that it had begun sudden large-scale military drills to test combat readiness.

Mariupol, a city of 400,000 before the invasion, has seen the bloodiest fighting, enduring weeks of siege and shelling.

A ceasefire broke down with some civilians still trapped in bunkers beneath the steel works despite a UN-brokered evacuation.

President Volodymyr Zelenskiy accused Russia of breaching agreements to pause fighting to allow civilians to escape.

"They're still fighting. They're still bombarding and shooting," Zelenskiy said via video link at a Wall Street Journal event. "We need a breather."

US President Joe Biden used a visit to a Lockheed Martin defence plant to press the US Congress to approve his proposed $33 billion assistance package for Ukraine, which includes more than $20 billion in military aid.

"If you don't stand up to dictators, history has shown us, they keep coming, they keep coming," Biden told workers at the plant in Alabama.

Britain announced an additional 300 million pounds ($375 million) in aid.