"Russia's appalling cruelty has caused immense human suffering and massive displacements, disproportionately affecting women and children" a declaration from a summit in Madrid said.

NATO leaders have funnelled billions of dollars of arms to Ukraine and faced appeals from President Volodymyr Zelensky for more artillery.

Alliance chief Jens Stoltenberg announced a new joint package of non-lethal support including secure communications equipment and anti-drone systems.

The assistance will also extend to training Ukrainian forces to pivot to more modern Western weapons over the longer term.

"Ukraine can count on us for as long as it takes," Stoltenberg said.