European Union foreign policy chief Kaja Kallas urged EU leaders on Thursday to pledge 5 billion euros for artillery shells for Ukraine to strengthen its hand in peace talks, amid divergences over how to bolster Kyiv and the EU's own military capabilities.

Arriving at an EU summit in Brussels, Kallas called on leaders to match words of support for Kyiv with deeds, as US President Donald Trump pushes ahead with his efforts to end the war, including through a rapprochement with Russia.

Kallas has scaled back a proposal to pledge up to 40 billion euros in military aid to Ukraine this year, with each country contributing according to its economic size, after resistance from some countries, particularly in southern Europe.

She told reporters she was now focusing on what Ukrainian President Volodymyr Zelenskiy – who was to address the summit by video link – says he needs most urgently, such as 2 million artillery shells at a cost of 5 billion euros.

"We should at least start to have a really concrete step – not only in words, but also in deeds that we are helping Ukraine right now. Because the stronger they are on the battlefield, the stronger they are behind the negotiating table," Kallas said.

Bolstering the EU's own defences also features on the summit agenda, reflecting deep fears that Moscow may attack an EU member in the coming years and doubts about the future of US protection for Europe via the Nato defence alliance.

Lithuania's President Gitanas Nauseda reiterated his support to Kyiv on Thursday, saying "Ukraine needs our military assistance. Ukraine needs long-range missiles and we are ready to provide it. We should increase the pressure on Russia."

"We have to rearm ourselves because otherwise we will be the next victims of Russian aggression," he added.

But some southern European capitals have been more reticent, reflecting a division between those geographically closer to Russia that have given more aid to Ukraine and those further away that have given less, as a share of their economies.

Spanish Prime Minister Pedro Sanchez said he did not like the term "rearm", which the European Commission has used extensively in its push for more defence spending.

"It is important to take into account that the challenges that we face in the southern neighbourhood are a bit different to the ones that the eastern flank faces," he said. (Reuters)