Nato leaders are gathering in Lithuania for a crucial summit that could shape the direction of the war in Ukraine and the future of the Western alliance.
The 31 allies hope to show Russia they have the resolve to support Ukraine militarily for the long term.
They arrive with a welcome boost after Turkey dropped its objections to Sweden joining the alliance.
But there remains disagreement over what to say about Ukraine's own ambitions of future membership.
It is thought some allies will promise Kyiv new security guarantees designed to deter future Russian aggression. They will also discuss providing more weapons and ammunition.
On the membership issue, Ukrainian President Volodymyr Zelensky wants Nato to say Ukraine could join as soon as possible after the fighting ends - setting out explicitly how and when this could be achieved.
But some Nato nations are reluctant to go too far, fearing the promise of near-automatic membership could give Russia an incentive both to escalate and drag out the war.
Jens Stoltenberg, the Nato secretary general, said no final decision had been made on the language of the final communiqué, but added: "I am absolutely certain that we will have unity and a strong message on Ukraine."
But after late night talks on Monday, he announced that Turkey had agreed to support Sweden's application to join Nato. The news was welcomed by the US and Germany, as well as Sweden itself.
Turkey had spent months blocking Stockholm's application, accusing it of hosting Kurdish militants. Mr Stoltenberg said the two sides had worked together to address Turkey's "legitimate security concerns".
Turkish President Recep Tayyip Erdogan earlier suggested he would back Sweden if the EU re-opened frozen membership talks with Ankara - a request that was rejected by EU officials.