Ukraine on Thursday escalated its demands for western firepower, seeking fighter jets and a bigger supply of tanks than the one being prepared by Nato allies.
It came as Ukraine was pounded by a new round of Russian drone and missile strikes on Thursday that killed at least 11 people, according to Ukrainian officials.
Britain said the first of its Challenger 2 tanks would arrive in Ukraine by March, as countries with Leopard tanks considered their next steps after Germany gave the green light to export them.
Along with US-made Abrams models, they are the first western battle tanks going to Ukraine and form part of a "tank coalition" sought by Kyiv.
Ukraine welcomed the announcements but said 300 to 500 tanks were needed for them to be a "game changer". The number currently envisaged is closer to 100. Ukraine has used tanks of Soviet design until now.
Visiting London to rally support for Ukraine, lobbyist Olena Halushka told The National that Ukrainians were “communicating a sense of urgency” to the West amid warnings of a spring offensive by Russia.
Ms Halushka, the co-founder of the International Centre for Ukrainian Victory, said the “next goal” would be to persuade the West to hand over fighter jets, despite fears of provoking Russia.
“At each and every step we heard that this is an escalation which will drag Nato into the war,” but this has not happened, she said.
“This is not only about tanks and armoured vehicles. When we get air superiority, we would be able to provide proper air assistance for our land troops.”
Germany Chancellor Olaf Scholz finally put German qualms aside to announce that 14 Leopards would be donated to Ukraine.
Perhaps more significantly, allies with German-made Leopards in their arsenals will be given the export licence to send them to Ukraine. Germany will also provide the necessary training and maintenance.
The goal is to form two Leopard battalions, which would typically have a few tank companies each ― suggesting about 100 Leopards in all.
Mr Scholz's long deliberation over the Leopards tested the patience of Nato allies. Supporters said he kept a cool head as he weighed up the risks of what Russia considers an escalation.
Poland Prime Minister Mateusz Morawiecki is urging allies to provide as many Leopards as possible after Poland scored a diplomatic win by persuading Germany to lift its veto.
Poland did not immediately say how many Leopards it would send, but had indicated last week that it was willing to offer one company of 14.
"I have been in touch with many prime ministers to make this coalition as broad as possible, so that modern weapons will allow us to repel another Russian offensive in Ukraine," Mr Morawiecki said on Thursday.
"Tanks are not for riding on a parade. Tanks are there to support those fighting in defence of freedom and sovereignty."
Finland: Defence Minister Mikko Savola said Finland, an applicant to join Nato, would join the tank coalition but that its contribution would be limited in scope.
"The international co-operation to send Leopards to Ukraine is advancing now and Finland will participate in that," Mr Savola said.
Norway Defence Minister Bjorn Arild Gram told broadcaster NRK that Norway "supports the donation of battle tanks to Ukraine ... Norway will take part".
He did not say how many would be sent to Ukraine. Reports in Norwegian media suggest eight could be provided out of a stock of 36.
Spain Defence Minister Margarita Roble said Spain was open to sending Leopards, although she said some were in poor repair and did not say they would definitely go to Ukraine.
"Spain is ready ... to deal with our allies in any way necessary, whether that means sending Leopards, training in the use of Leopards or help in their maintenance and upkeep," she said.
Netherlands Dutch Prime Minister Mark Rutte said the Netherlands was prepared to deliver battle tanks to Ukraine if needed. It has previously worked with Berlin to export German-made howitzers to Ukraine.
"If a contribution from the Netherlands helps, we are prepared to do so," Mr Rutte told broadcaster RTL.
Weapons and drones supplied to Ukraine - in pictures
US and UK tanks
US President Joe Biden announced on Wednesday that Ukraine would receive 31 Abrams battle tanks, although officials said delivery would take months rather than weeks.
The tanks, described by Mr Biden as the most capable in the world and previously used in the conflicts in Iraq and Afghanistan, will come with eight M88 support vehicles.
The U-turn, after Washington previously suggested the Abrams were not suitable for Ukraine, was seen as a concession to Mr Scholz to ease German discomfort about sending the Leopards.
Britain has already announced it will send a squadron of 14 Challenger 2 tanks, along with armoured recovery and repair vehicles and ammunition.
Ukrainian President Volodymyr Zelenskyy said in an overnight address that "the key thing now is speed and volume".
"We must form a tank fist, a fist of freedom whose hits will not let tyranny stand up again," he said.
Ukrainian officials said another round of drone and missile strikes pounded the country on Thursday morning. Some are calling for western fighter jets in a next stage of military aid.
Senior diplomat Andrij Melnyk said a Ukrainian victory was "scarcely imaginable" without a modern air force.
But Lord Richard Dannatt, a former chief of Britain's general staff, told Sky News it was "not realistic" for the West to send modern fighter jets because the training required would be too much.