ZAPORIZHZHIA, Ukraine (AFP)— A desperate attempt to evacuate civilians from Mariupol failed Wednesday as the strategic Ukrainian port appeared close to finally falling under Russian control after weeks of relentless attack.

Raising tensions, Russia said it had tested a new nuclear-capable intercontinental ballistic missile, though the United States said it had been notified and the test was not deemed a threat.

In the latest ultimatum issued in its battle to capture Mariupol after a horrific two-month siege, Moscow made another call for the city’s defenders to surrender.

Kyiv said early Wednesday it had agreed with Russian forces to open a safe route for civilians to flee the devastated city.

But Ukrainian Deputy Prime Minister Iryna Vereshchuk said later the bid “did not work” and efforts would resume Thursday.

A Ukrainian commander in the besieged Azovstal steel plant issued a desperate plea for help, saying his marines were “maybe facing our last days, if not hours”.

“The enemy is outnumbering us 10 to one,” said Serhiy Volyna from the 36th Separate Marine Brigade.

“We appeal and plead to all world leaders to help us. We ask them to use the procedure of extraction and take us to the territory of a third-party state.”

As fighting raged in Ukraine’s east and south, European Council leader Charles Michel visited Kyiv and vowed the EU would do “everything possible” to help Ukraine win the war.

“You are not alone. We are with you,” Michel said during a press conference alongside Ukrainian President Volodymyr Zelensky.

But Zelensky said Ukraine still did not have enough weapons to resist the invasion, despite military aid from Western allies.

– Eastern offensive –

Control of Mariupol and the separatist-controlled eastern Donbas region would allow Moscow to create a southern corridor to the Crimean Peninsula that it annexed in 2014, depriving Ukraine of much of its coastline.

Fighting flared back up this week after Russia launched a major offensive into Donbas.

The battle for Mariupol appeared to be nearing a tipping point, after nearly two months of devastating fighting that has seen untold numbers of civilians trapped and killed.

An adviser to the mayor of Mariupol described a “horrible situation” in the encircled steel plant and reported that up to 2,000 people — mostly women and children — are without “normal” supplies of drinking water, food and fresh air.

Svyatoslav Palamar, a commander in the nationalist Azov battalion defending Mariupol, said the Russian attack on the sprawling complex was relentless.

“Powerful bombs have been dropped several times on Azovstal, we have been bombed from boats… we are under siege. The front is 360 degrees,” said Palamar in a post on Telegram.

“The situation is critical, we call on international leaders to help the children,” he added.

– ‘Violent deaths’ –

Russia said Wednesday its forces had launched 73 air strikes across Ukraine, hitting dozens of locations where Ukrainian troops were concentrated.

In eastern Ukraine’s Kramatorsk, a large city in the Donetsk region, residents were already bracing for the worst.

“It’s going to be a mess,” said Alexander, 53. “There’s nothing good to expect.”

Further from the frontlines, residents were still reeling weeks after Russian forces withdrew from the area near the capital Kyiv.

At a morgue in Bucha, families carefully searched body bags and examined cadavers looking for missing loved ones.

In the car park of the small communal morgue, body bags arrived in carts or were piled up in trailers, vans and non-refrigerated trucks.

Four hundred bodies have been discovered there since the Russians withdrew on March 31, local police chief Vitaly Lobas told AFP. Around a quarter of them are still unidentified.

“The majority died violent deaths” and were shot, Lobas said.

Ukrainian authorities have said that over 1,200 bodies have been found in the Kyiv region so far.

– ‘War crimes’ –

President Vladimir Putin has said he launched the so-called military operation in Ukraine in February to save Russian speakers in the country from a “genocide” carried out by a “neo-Nazi” regime.

Russian Foreign Minister Sergei Lavrov accused “nationalist” Ukrainian forces of using civilians as human shields and of refusing to evacuate via humanitarian corridors.

But his forces have faced allegations of war crimes — most recently from the EU’s Michel, who toured the devastated nearby town of Borodianka Wednesday.

“History will not forget the war crimes that have been committed here,” Michel wrote on Twitter.

Putin said Wednesday’s test of the Sarmat intercontinental ballistic missile would make the Kremlin’s enemies “think twice”.

At a G20 meeting Wednesday, US Treasury Secretary Janet Yellen led a multi-nation walkout of finance officials from the world’s richest countries when Russian officials spoke, in protest against Moscow’s invasion.