President Volodymyr Zelensky pressed a NATO summit Thursday to flood weapons into Ukraine and Western allies responded with new sanctions against Russia, promises of military aid, and discussion of expelling Moscow from the international G20 body.
As battles raged across Ukraine, with television footage showing a large Russian warship ablaze at dockside near the southern city of Mariupol, Zelensky addressed the emergency NATO summit and a G7 leaders' meeting by video link.
He said the West should provide "all the weapons we need" to "prevent the deaths of Ukrainians from Russian strikes, from Russian occupation."
Kicking off a day of intense diplomacy, US President Joe Biden made clear that the Western alliance was listening.
"NATO has never been more united," Biden said.
And after Zelensky said there was a "real" chance of Russian President Vladimir Putin resorting to chemical warfare, Biden told reporters "we will respond if he uses it."
Biden noted that under his presidency the United States has pledged $2 billion in weapons to Ukraine. He announced a new commitment to "more than $1 billion in humanitarian assistance," as well as promising to welcome 100,000 of the nearly 3.7 million refugees fleeing the country.
After the United States announced new sanctions, including targeting Russian politicians, Biden said the West was in it for the long haul, intent on "increasing the pain" on Moscow.
Biden intensified the effort to ostracize Putin's Russia with a call to exclude Moscow from the G20.
"That was raised today," Biden told reporters, adding that if the group of 20 countries does not agree, then he would press for Ukraine to be allowed to join.
In his address, Zelensky said that Russia was using phosphorus bombs, which cause severe burns, conducting indiscriminate shelling of civilians, and could resort to "full-scale use" of chemical weapons.
Ukraine has already lived through "a month of heroic resistance. A month of the darkest suffering," he said. "To save people and our cities, Ukraine needs military assistance without restrictions."
- 'Barbarism' -
On the ground, long-range Russian strikes on the eastern city of Kharkiv killed at least six civilians and wounded more than a dozen, Ukrainian authorities said.
At least four people including two children were killed in strikes elsewhere in the east, Lugansk governor Sergiy Gayday said, accusing Russian forces of using phosphorus on the village of Rubizhne.
Britain's ITV network showed footage of the incendiary weapons dropping in a white haze overnight on the commuter town of Irpin near Kyiv.
The scale of civilian suffering was underscored when the UN said more than half of the country's children have been driven from their homes by Russian bombardment.
"Vladimir Putin has already crossed the red line into barbarism," British Prime Minister Boris Johnson said in Brussels.
Ukrainian forces claimed to be pushing Russian troops back in some areas around Kyiv. They also claimed success in attacking one of the navy vessels used to bring Russian forces in from the Black Sea.
Video footage showed a ship in a ball of fire and smoke, with other vessels that had been nearby heading away from the inferno.
- NATO reinforces eastern flank -
Zelensky wants NATO to help Ukraine go on the offensive with more advanced fighter jets, missile defense systems, tanks, armored vehicles and anti-ship missiles.
NATO members have supplied a steady stream of weapons including anti-tank rockets, which have helped to stall Russia's advance. But these are seen as essentially defensive.
The United States has so far ruled out sending airplanes or other large weapons systems to Ukraine. Biden says he does not want to cross a line into what he says could become "World War 3" pitting nuclear-armed Russia against NATO.
However, NATO Secretary General Jens Stoltenberg announced new deployments to eastern flank members Romania, Hungary, Slovakia and Bulgaria, as well as bolstering chemical and nuclear defenses in case Russia expands its attack beyond Ukraine.
Biden said that NATO unity showed "Putin is getting exactly the opposite of what he intended."
- 'Grim milestone' -
Zelensky's appeal to NATO came one month to the day after Russian tanks rolled over the border, acting on Putin's plan to force pro-Western Ukraine back into Moscow's orbit.
Since then, thousands of civilians, as well as thousands of soldiers from the two sides, are believed to have been killed. More than 10 million Ukrainians have fled their homes.
And the month of war has displaced 4.3 million children -– more than half of Ukraine's estimated child population of 7.5 million.
"This is a grim milestone that could have lasting consequences for generations to come," Unicef chief Catherine Russell said.
UN figures show that nearly 3.7 million Ukrainians have fled abroad, and more are now displaced inside Ukraine after harrowing journeys out of cities like Mariupol.
In the besieged southern port, Zelensky says nearly 100,000 people are trapped without food, water or power and enduring fierce shelling by Russian forces.
The city is a treasured prize for Russia as it would enable a land-bridge between Russian-annexed Crimea and regions already controled by Russian proxy forces in eastern Ukraine.
Intense fighting has made the city all but inaccessible.
Ramzan Kadyrov, the warlord leader of Russia's Chechnya region, claimed on Thursday that his forces had taken control of city hall there.
Meanwhile, in Zhytomyr, a garrison town west of Kyiv, a Russian strike flattened the school where Vasiliy Kravchuk's six-year-old son was meant to start next year.
"Every day it's 20, 30 times we go to the basement (to shelter). It's difficult because my wife is pregnant, I have a little son," sobbed the 37-year-old, who before the war worked in tourism.
- Tarnishing Russian gold -
While the Moscow Stock Exchange partially reopened for the first time since the invasion, the G7 summit in Brussels vowed new action to destabilize Russia's tottering economy.
The group of advanced economies and the EU pledged to block transactions involving the Russian central bank's gold reserves, to hamper any Moscow bid to circumvent Western sanctions.
Russia's isolation on the world stage was underscored by a second non-binding UN General Assembly resolution demanding an immediate halt to the war, which was approved by 140 countries, with 38 abstaining and five voting against.
(Except for the headline, this story has not been edited by NDTV staff and is published from a press release)