Ukrainian President Volodymyr Zelensky on Thursday pressed a NATO summit to flood weapons into Kyiv and Western allies responded with new sanctions against Russia, promises of military aid, and discussion of expelling Moscow from the international G20 body.

As the conflict 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.

Also read: Ukraine arrests foreigner helping draft dodgers flee to Moldova for $1,500

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.

Also read: Ukrainian band urges Ed Sheeran to join remote Kyiv concert ‘under the bombs’

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.

Also read: Explained: A look at weapons used by Russia in war against Ukraine

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 ostracise Putin’s Russia with a call to exclude Moscow from the G20.

Also read: China denies having ‘prior knowledge’ of Russia’s plans to invade Ukraine

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.