Sunak addressed fellow leaders of Joint Expeditionary Force nations in Latvia, where Ukraine's president, Volodymyr Zelensky, urged the West for more weapons, Ukrinform reports, referring to Sky News.
Sunak said the alliance must deliver more military aid to Ukraine including additional air defense systems, artillery and armored vehicles.
"We must be clear that any unilateral call for a ceasefire by Russia is completely meaningless in the current context. I think it would be a false call, it would be used by Russia to regroup, to reinforce their troops. And until they have withdrawn from conquered territory there can and should be no real negotiation," he said.
Instead, Sunak says the alliance must continue to focus on "degrading Russia's capability to regroup and resupply."
This involves "going after its supply chains and removing the international support", in particular being "strong" about criticizing Iran for supplying drones to Moscow, he said.
Appearing via video link, Zelensky asked the leaders for a wide range of weapons systems just hours after Kyiv came under attack by Russian drone attacks.
On the night of December 19, Russia carried out another massive attack using Shahed kamikaze drones from a new batch of 250 UAVs supplied by Iran. The Ukrainian Air Force shot down 30 out of 35 drones launched by Russia.