The United States and EU announced Friday a new drive to wean Europe off Russian gas imports and so choke off the billions in revenues that are fuelling Moscow's ruinous war against Ukraine.
A clearer scale of the ruin emerged from Ukraine's besieged port city of Mariupol, which a month into the invasion now resembles scenes of Russian cities razed by the Nazis in World War II.
Authorities said some 300 civilians may have died in a Russian air strike on a theatre-turned-bomb shelter last week, in what would be the invasion's single bloodiest attack.
After a trio of summits in Brussels, US President Joe Biden warned that NATO would "respond" if Russia's Vladimir Putin resorts next to chemical weapons as part of his aggression against a Western-leaning democracy.
"The nature of the response would depend on the nature of the use," Biden said.
Kremlin spokesman Dmitry Peskov accused Biden of seeking to "divert attention", and also denied Ukrainian claims that Russia had broken international law by dropping incendiary phosphorus bombs on civilians.
Biden and EU commission chief Ursula von der Leyen announced a joint energy task force in Brussels, before he headed to the eastern Polish town of Rzeszow, a mere 80 kilometres (50 miles) from Ukraine.
Taken together, Western sanctions are "draining Putin's resources to finance this atrocious war", von der Leyen told reporters alongside Biden.
On the battlefield, Moscow said it had destroyed Ukraine's largest remaining military fuel depot, at Kalynivka near the capital Kyiv, using sea-borne cruise missiles.
Fireballs leapt into the air from the storage facility, while a smaller fire blazed from a severed fuel line and a huge plume of black smoke rose over the site, AFP reporters at the scene said.
"Fortunately, there were no casualties," a security guard said at a checkpoint near the depot, asking not to be identified.
But in the east, Russian strikes targeting a medical facility in Ukraine's second city Kharkiv killed four civilians and wounded several others, police said.
"I had gone out looking for bread. There were explosions. When I came back there were four bodies lying there, with relatives crying by their side," 71-year-old Mykola Hladkiy told AFP.
Several residents said cluster munitions were used, and AFP journalists saw large fires after other strikes in Kharkiv.
NATO, European Union and G7 leaders in Brussels shied away from impassioned demands by Ukrainian President Volodymyr Zelensky for more advanced weapons systems to take the fight to the invaders.
He underlined the toll inflicted by incessant Russian bombardment of cities such as the southern port of Mariupol -- where authorities said a horrifying picture was emerging from the Drama Theatre.
Up to 1,000 civilians were said to be sheltering in the theatre when it was flattened by a Russian bomb last week. Ukraine said efforts to dig people out of the ruins were hampered by relentless bombardment.
"From eyewitnesses, information is emerging that about 300 people died in the Drama Theatre of Mariupol following strikes by a Russian aircraft," Mariupol city hall wrote on Telegram.
Zelensky says nearly 100,000 people are trapped without food, water or power in the besieged city.
Addressing the EU summit late Thursday by video feed, he thanked countries including Poland and Estonia for their support, noted German backing came "a little later" -- and singled Hungary out for censure.
"You have to decide for yourself who you are with," Zelensky told Hungary's right-wing populist leader Viktor Orban, who has close ties to Moscow.
"Listen, Viktor, do you know what's going on in Mariupol?" he added.
While Mariupol is now a charred ruin, Western defensive systems including shoulder-fired anti-tank missiles have helped Ukraine's armed forces hold their line.
"Ukrainian counter-attacks, and Russian forces falling back on overextended supply lines, has allowed Ukraine to re-occupy towns and defensive positions up to 35 kilometres (22 miles) east of Kyiv," Britain's defence ministry said in a daily update.
After several rounds of sanctions banished Russia from much of Western finance, Ukraine's EU allies broadened their economic offensive to energy, which largely powers European homes and industry.
Biden and von der Leyen said the United States would strive to help supply Europe with an extra 15 billion cubic metres of liquefied natural gas this year -- replacing one-third of supplies from Russia.
Germany, Moscow's biggest customer in Europe, said it would halve Russian oil imports by June and end all coal deliveries by the autumn.
"The first important milestones have been reached to free us from the grip of Russian imports," Economy Minister Robert Habeck said.
In Poland, Biden will meet members of the US 82nd Airborne Division, part of NATO's increasingly muscular deployment to its eastern flank.
He will also receive a briefing on the dire humanitarian situation in Ukraine, which nearly 3.7 million people have fled, mostly to Poland.
The UN believes that more than half of Ukraine's children have already been driven from their homes, "a grim milestone that could have lasting consequences for generations to come", according to Unicef chief Catherine Russell.
In the flashpoint town of Irpin on Kyiv's north-western outskirts, little Daria played with her dinosaur mittens as a yellow evacuation bus took her family and others away. It was her fourth birthday on Thursday.
"We were planning some candles and a cake, but we had to leave it there," said Daria's mother Susanna Sopelnikova, 29, holding her tightly on her lap.
"We stayed in the basement for about three weeks, then we decided to leave," said Sopelnikova, as Daria's six-year-old brother Yehor sat silently next to their father Anatolii to the distant boom of shelling.
After the Putin regime imposed an information blackout on its "special military operation", most Russians are unaware of the true picture of fighting in Ukraine.
But an exhibition of 24 shocking images opened on Friday at a train station in Lithuania used by Russians transiting from the exclave of Kaliningrad.
On some of the pictures, exhibited at the height of the carriage windows, an inscription read: "Today, Putin is killing the peaceful population of Ukraine. Do you approve of this?"
Wearing underpants stained red, the demonstrator shouted and posed for photographers before being led off by security guards
Europe4 days ago
Finnish state-owned wholesaler Gasum confirmed on Saturday that the flows have stopped
Europe4 days ago
There was no immediate confirmation from Kyiv
Europe4 days ago
Liz Truss says the United Kingdom and other alliance members are discussing the possibility of sending modern weaponry
Europe4 days ago
Ukrainian Prime Minister thanks European Commission President for the aid
Europe4 days ago
Scientists not expecting the outbreak to evolve into a pandemic like Covid-19
Europe5 days ago