KYIV (REUTERS) - Local authorities in the Ukrainian city of Mariupol accused Russian forces on Friday (May 6) of opening fire on a car on its way to evacuate civilians from a vast steel works, killing a fighter and violating a ceasefire agreement.

Russia did not immediately comment on the city council’s statement. Moscow has denied targeting civilians and had offered a ceasefire to allow the evacuation of civilians trapped in the Azovstal steel plant with Ukrainian fighters.

“During the ceasefire on the territory of the Azovstal plant a car was hit by Russians using an anti-tank guided weapon. This car was moving towards civilians in order to evacuate them from the plant,” Mariupol city council said in an online post.

“As a result of the shelling, one fighter was killed and six were wounded. The enemy continues to violate all agreements and fails to adhere to security guarantees for the evacuation of civilians.” Reuters could not verify the city council’s statement.

Russian forces have occupied Mariupol, leaving the city’s last defenders – and scores of civilians – holed up in the Azovstal plant.

The United Nations and the International Committee of the Red Cross (ICRC) have helped evacuate some of the civilians and Ukraine said a new attempt was under way to evacuate the civilians.

Heavy fighting with Russian forces thwarted efforts to bring them to safety on Thursday.

Mariupol, a strategic southern port on the Azov Sea, has endured the most destructive siege of the 10-week-old war and the sprawling Soviet-era Azovstal steel plant is the last part of the city still in the hands of holdout Ukrainian fighters.

UN-brokered evacuations of some of the hundreds of civilians who had taken shelter in the plant's network of tunnels and bunkers began last weekend, but were halted in recent days by renewed fighting.

Ukraine has appealed to Medecins Sans Frontieres (Doctors Without Borders) to help evacuate fighters holed up in the steel works.

Ukraine’s Ministry for the Reintegration of the Temporarily Occupied Territories said it had written to the medical charity and asked it to assess the fighter’s physical and mental condition, collect evidence of the conditions they are in and provide medical assistance to “Ukrainians whose human rights have been violated by the Russian federation”. 

Russia has turned its heaviest firepower on Ukraine's east and south, after failing to take the capital Kyiv in the early weeks following its Feb 24 invasion. The new front is aimed at limiting Ukraine's access to the Black Sea, vital for its grain and metals exports, and linking Russian-controlled territory in the east to the Crimea Peninsula, seized by Moscow in 2014.

Moscow calls its actions a "special military operation" to disarm Ukraine and rid it of anti-Russian nationalism fomented by the West. Ukraine and the West say Russia launched an unprovoked war of aggression. More than 5 million Ukrainians have fled abroad since the start of the invasion.

Ukraine's general staff said on Friday that Russian forces were continuing their "attempts to fully take over the Donetsk and Luhansk regions", areas in the east partially seized by Moscow-backed separatists in 2014.

Russia's defence ministry said it had destroyed a large ammunition depot in the eastern Ukrainian city of Kramatorsk in a missile strike. It also said its air defences shot down two Ukrainian warplanes in the Luhansk region.

It was not possible to independently verify either side's statements about events on the battlefield.

'Victory Day in Mariupol'

In Mariupol, Ukraine’s general staff said Russian efforts to overrun the Azovstal plant had resumed, with air support.

An estimated 200 civilians remained trapped underground in the Azovstal plant with little food or water.

Russian President Vladimir Putin has said Moscow was prepared to provide safe passage for the civilians but reiterated calls for Ukrainian forces inside to disarm.

The Kremlin denies Ukrainian allegations that Russian troops stormed the plant in recent days and said humanitarian corridors were in place. Russia’s military promised to pause its activity for the next two days to allow civilians to leave.

Aerial footage of the plant, released on Thursday by Ukraine's Azov Regiment, showed three explosions striking different parts of the vast complex, which was engulfed in heavy, dark smoke. Reuters verified the footage location by matching buildings with satellite imagery, but was unable to determine when the video was filmed.

Putin declared victory in Mariupol on April 21 and ordered his forces to seal off the plant.

Ukrainian officials have said Russia might step up its offensive before May 9, when Moscow commemorates the Soviet Union's victory over Nazi Germany in World War II.

“The time will come to mark Victory Day in Mariupol,” Kremlin spokesperson Dmitry Peskov told reporters in a briefing on Friday, when asked about plans for May 9 in territory recently seized by Russian-backed forces.

'Hospitals devastated'

Ukrainian President Volodymyr Zelensky said on Thursday that nearly 4,000 hospitals and other medical facilities in the country had been destroyed on damaged since the invasion.

"This amounts to a complete lack of medication for cancer patients. It means extreme difficulties or a complete lack of insulin for diabetes," Zelensky said in a video address to a medical charity group. "It is impossible to carry out surgery. It even means, quite simply, a lack of antibiotics."

The Kremlin says it targets only military or strategic sites and not civilians. Ukraine daily reports civilian casualties from Russian shelling and fighting, and accuses Russia of war crimes. Russia denies the allegations.

Oil embargo

The stubborn Ukrainian defence of Azovstal has underlined Russia's failure to take major cities in a war that has united Western powers in arming Kyiv and punishing Moscow with the most severe sanctions ever imposed on a major power.

Economic measures from Washington and European allies have hobbled Russia's US$1.8 trillion (S$2.5 trillion) economy while billions of dollars worth of military aid has helped Ukraine frustrate the invasion.

In an apparent crack in Western unity, however, Hungarian Prime Minister Viktor Orban said on Friday his country could not support the European Union's proposed new sanctions package, which includes an oil embargo, in its present form.

Orban said the European Commission's current proposal would amount to an "atomic bomb" dropped on the Hungarian economy, adding that Hungary was ready to negotiate.

Three sources later told Reuters that the EU executive would amend its proposal, extending the period before the embargo took effect for Hungary, Slovakia and the Czech Republic to give the more time to upgrade their own oil infrastructure.

The Kremlin has said Russia is weighing responses to the EU plan.