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US President Joe Biden, British Prime Minister Boris Johnson and Canadian Prime Minister Justin Trudeau pledged on Tuesday to send more artillery weaponry to Ukraine in the face of an all-out Russian assault on that country's East.
Mr Biden spoke with Mr Johnson, Mr Trudeau and other allied leaders in a secure video call from the White House Situation Room as the Russian invasion reached a new phase.
Asked by reporters during a visit to New Hampshire if the United States would be sending more artillery to Ukraine, Mr Biden replied yes, according to Reuters.
In the 90-minute video call, the leaders discussed ongoing support for Ukraine in the form of security, economic and humanitarian assistance, the White House said.
"The leaders affirmed their solidarity with the Ukrainian people and condemned the humanitarian suffering caused by Russia’s unprovoked and unjustified invasion," the White House said in a readout of the call.
"They also discussed their co-ordinated efforts to impose severe economic costs to hold Russia accountable."
Mr Biden called the meeting against the backdrop of the battle for the Donbas region, where wide-open farmland lends itself to artillery exchanges more than the urban battles mainly seen in the war to date.
Ukrainian President Volodymyr Zelenskyy is calling on allies to offer more support for his country's military amid fierce clashes in the east of the country.
Mr Biden discussed the crisis with representatives of the G7, Nato and EU, including the leaders of the UK, France, Germany, Italy, Canada, Japan, Poland, and Romania.
Mr Johnson used the call to stress the “critical need” for further military support for Ukraine, Downing Street said.
A spokesman for Mr Johnson said a senior national security told the Cabinet that the offensive in the Donbas was likely to be prolonged and bloody.
"The next phase of the war was likely to be an attritional conflict that could last several months," the spokesman said.
Speaking before the online leaders meeting, a Nato military chief said each nation “makes their own choice” when it comes to what types of weapons to send to Ukraine.
Countries have recently started to send heavier weaponry to Ukraine, Lt Gen Lance Landrum, deputy chairman of the Nato military committee, said at the Invictus Games in The Hague.
Asked whether more countries could dispatch anti-aircraft vehicles to Ukraine, he told PA: “I think each nation makes their own choice. Each nation is sending aid to Ukraine in a bilateral relationship with Ukraine.
“The different types of equipment that they send are based on the national sovereign rights in the negotiations that they have with the Ukrainian government.
“But I think that, in general, we have seen an increase in heavier-type weapons, defensive weapons, to help them in their fight, particularly as the fighting escalates in the east.”
Asked how he would assess Ukraine’s military strength, he said it had shown a “huge fighting spirit” and was creative in its tactics.
Lt Gen Landrum was asked what he would say to those frustrated with Nato’s decision not to intervene directly in the war and said the alliance was “focused on the deterrence and defence for the allied nations".
"We are in great support of Ukraine, the Ukrainian forces, the Ukrainian citizens and their government," he said.
Mr Zelenskyy has repeatedly issued warnings about the risk of the war spilling over into other European countries – including Nato members – if Russia's ambitions are not curbed.
On Sunday, Ukraine asked G7 nations to pledge $50 billion in financial support, said Oleh Ustenko, Mr Zelenskyy's economic adviser.
Kyiv is also considering issuing 0 per cent coupon bonds to help it cover a war-linked budget deficit over the next six months, Mr Ustenko said.
“The president has asked G7 countries to provide $50bn in funding for Ukraine. We are using several parallel routes at the same time,” Mr Ustenko said.
Kyiv is also considering whether to request a Special Drawing Rights loan from the International Monetary Fund, he said.
He said Ukraine was recording losses of about $7bn a month, which would add up to about $50bn over a six-month period.
A representative for the Pentagon said “of course they can win this”, when asked about the Ukrainians’ prospects in the war against Russia.
The Russian Defence Ministry said it struck 1,260 targets in Ukraine overnight.
On Tuesday, the UK’s tax authority, HM Revenue and Customs, announced plans to revoke the Moscow Stock Exchange’s status as a recognised stock exchange in response to the invasion.
The move would remove some tax relief for investors.
"Revoking Moscow Stock Exchange’s recognised status sends a clear message – there is no case for new investments in Russia," said Lucy Frazer, the UK's Financial Secretary to the Treasury.
Germany, a member of the G7 and Nato, appears to be sceptical about pledging to ship more weapons to Ukraine.
Chancellor Olaf Scholz was last week accused by his coalition partners of stalling on commitments to arm Ukrainian forces.
Mr Scholz initiated a historic reversal of Germany’s previous frugal defence policy in the early stages of the invasion. But he has since appeared hesitant to push beyond initial supplies of protective equipment, munitions and rockets for Ukraine.
His position risks undermining his country’s image abroad as a reliable ally, said Anton Hofreiter, who leads the German parliament’s Europe committee.
“The problem is in the chancellery,” he told RTL television.
“We must now finally begin supplying Ukraine with what it needs, and that includes heavy weapons.”
Spanish Prime Minister Pedro Sanchez will travel to Kyiv this week to meet Mr Zelenskyy, a government source in Madrid said.
Mr Sanchez will be the latest in a series of world leaders to travel to the Ukrainian capital since Russian forces withdrew from surrounding towns and villages.