KYIV, AFP — Russian forces stepped up the pressure on Kyiv on Saturday and pummelled civilian areas in other Ukrainian cities, including hospitals in Mykolaiv and a mosque in Mariupol, the port city already devastated by two weeks of siege.

Russian strikes destroyed the airport in the town of Vasylkiv on Saturday morning, about 40 kilometres (25 miles) south of Kyiv, while an oil depot was also hit and caught fire, the mayor said.

The northwest suburbs of the capital, including Irpin and Bucha, have already endured days of heavy bombardment while Russian armoured vehicles are advancing on the northeastern edge.

Ukrainian presidential adviser Mykhailo Podolyak on Friday called it a “city under siege”.

AFP reporters in Kyiv said Saturday there was a column of thick black smoke rising from the eastern suburbs, but no sign yet of ground forces moving into the outskirts.

Other cities have been utterly devastated following Russia’s invasion of its neighbour on February 24, with civilians targeted in what the United Nations warned could amount to war crimes.

The southern port city of Mariupol is facing what Ukrainian Foreign Minister Dmytro Kuleba called “the worst humanitarian catastrophe on the planet”, with more than 1,500 civilians dead in 12 days.

Russian forces shelled a mosque there where 80 civilians were sheltering, the foreign ministry said Saturday, without specifying the time of the attack or casualties.

A new attempt was planned Saturday to help civilians evacuate the city, via a humanitarian corridor to Zaporizhzhia, around 200 kilometres to the north east, Kyiv said.

Meanwhile an AFP reporter in the southern city of Mykolaiv said a hospital in the northern district of Ingulski came under fire, while heating is out in the area, forcing many residents to flee.

“They shot at the civilian areas, without any military objective,” said the hospital’s head, Dmytro Lagochev, adding: “There’s a hospital here, an orphanage and a ophthalmological clinic.”

The United Nations estimates that 2.5 million people had fled Ukraine since the invasion, most of them to Poland, in the worst refugee crisis since World War II.

Pay the price

As Russia widens its bombardment and talks between Moscow and Kyiv seemingly go nowhere, pleas by Ukrainian President Volodymyr Zelensky for NATO to intervene have grown increasingly desperate.

Washington and its EU allies have sent funds and military aid to Ukraine.

But US President Joe Biden on Friday again ruled out direct action against nuclear-armed Russia, warning that it would lead to “World War III”.

Instead, Washington added more layers of sanctions to those already crippling Russia’s economy, this time ending normal trade relations and announcing a ban on signature Russian goods vodka, seafood and diamonds.

The United States and the European Union also suspended the export of their luxury goods to Russia.

Russian President Vladimir “Putin must pay the price,” Biden said from the White House.

‘Cinders in his lungs’

The situation in Mariupol remains “desperate”, according to Doctors Without Borders, with no water or heating — and running out of food.

“Hundreds of thousands of people… are for all intents and purposes besieged,” Stephen Cornish, one of those heading the medical charity’s Ukraine operation, told AFP in an interview.

“Sieges are a medieval practice that have been outlawed by the modern rules of war for good reason.”

Zelensky said they were trying to arrange evacuations from besieged cities but Russian forces were disrupting efforts.

The central city of Dnipro, an industrial hub of one million inhabitants, saw its image as a relatively safe haven shattered when three missiles hit civilian buildings Friday.

Images of its charred or destroyed buildings — including a kindergarten with windows blown out — now join those from Kharkiv and Mariupol as testimony to the brutal conflict.

“Today, we were supposed to host people who need a lot of support,” said Svetlana Kalenecheko, who lives and works in a clinic that was damaged.

“Now we can’t help anyone.”

In Kharkiv, in the east, doctors at a hospital described spending two days pumping ash from the stomach of an eight-year-old child whose home was blasted by a Russian missile.

“He still has cinders in his lungs,” Dima Kasyanov’s doctor told AFP.

The attacks on civilians prompted a new flurry of warnings on Friday that Russia is committing war crimes.

“We are really heading towards an unimaginable tragedy,” warned Cornish, of Doctors Without Borders, insisting that “there is still time to avoid it, and we must see it avoided”.

Foreign combatants

In a video address released Saturday, Zelensky appealed to Russian mothers to prevent their sons from being sent to war.

“I want to say this once again to Russian mothers, especially mothers of conscripts. Do not send your children to war in a foreign country,” he said.

Zelensky said more than 12,000 Russian troops had been killed in the invasion.

US estimates put the number of Russian fatalities at 2,000 to 4,000 while Moscow’s only official toll, announced last week, said 498 Russian troops had been killed.

Foreign combatants have already entered the Ukrainian conflict on both sides, and on Friday, the Kremlin ramped up efforts to bring in reinforcements, particularly from Syria.

A furious Zelensky accused Russia of hiring “murderers from Syria, a country where everything has been destroyed… like they are doing here to us”.

In southern Ukraine, Russian soldiers abducted the mayor of Melitopol, which Zelensky said was a “sign of weakness” and a “crime against democracy”.

The global ripple effects of the conflict continued elsewhere.

Last-minute Russian demands related to the conflict threatened to derail the near-complete process of reviving the Iranian nuclear deal Friday.

And the fighting spurred vows to bolster the European Union’s defences, with EU leaders describing the invasion as a wake-up call.

“There’s no denying the fact that two weeks ago we woke up in a different Europe, in a different world,” European Council chief Charles Michel said.

Russia also moved Friday to block Instagram and launch a criminal case against its owner Meta, as Moscow fired back at the tech giant for allowing posts calling for violence against Russian forces.

‘Serious diplomacy’

Putin said Friday there were some “positive shifts” in talks with Ukraine and negotiations were being held “almost daily”.

But US Vice President Kamala Harris, speaking in Bucharest, said the Russian leader had shown “no sign of engaging in serious diplomacy”.

At the United Nations, Western countries accused Russia of spreading “wild” conspiracy theories after Moscow’s envoy told diplomats that America and Ukraine had researched using bats to conduct biological warfare.

The US envoy said Russia had made the claims as part of a “false flag effort” for using chemical weapons of its own in Ukraine.

Biden warned Russia would pay a “severe price” if it used chemical weapons — but added: “We will not fight a war against Russia in Ukraine”.