Ukraine is banking on producing more of its weapons to fight Russia in 2024 as it faces a potential drop-off in western military aid.
Russian President Vladimir Putin, meanwhile, sounded a confident note on Monday as he vowed the Kremlin's forces would intensify strikes on Ukraine.
With the war nearing the two-year mark, the future of western aid for Ukraine is uncertain with support from the US in limbo while President Joe Biden seeks more funds from Congress.
“Next year, the enemy will feel the wrath of domestic production,” Ukrainian President Volodymyr Zelenskyy said in a New Year address cut with footage of Ukrainian artillery and fighter jets.
He said Ukrainian-made shells, naval weapons and “at least a million” drones would be part of an arsenal “which we will generously use”.
Mr Putin, who alluded only briefly to the war in his official New Year's message, spoke on a visit to a military hospital to vow retaliation for Ukrainian attacks on mainland Russia.
"We're going to intensify the strikes, no crime against civilians will rest unpunished, that's for certain," he said.
Mr Putin claimed Moscow now holds the "strategic initiative" in the war, as he described Ukrainian forces as "gradually deflating".
He said Russia does not want to fight "endlessly" but said any end to the conflict would come "only on our terms", without revealing what those conditions would be.
Russia invaded Ukraine in February 2022 but its hopes of a swift knockout blow were soon foiled and the war has reached a near-stalemate on land, even as Ukraine touts naval gains in the Black Sea.
Mr Zelenskyy hailed the arrival of western tanks and missile defences during 2023 as a rebuke to “attempts to diminish global solidarity”.
Small Ukrainian gains in a counter-offensive, fatigue after two years of war and the outbreak of the Israel-Gaza war have also cast doubt on the West's stamina.
Britain, though, announced last week it was sending hundreds more air defence missiles after Ukraine was struck by Russia's biggest aerial barrage of the war.
Ukraine reported further attacks in the first hours of 2024, with air force commanders saying they destroyed 87 out of 90 Russian drones.
One person was killed in the southern Odesa region, where Ukraine said attacking Black Sea port infrastructure was Russia's “clear priority”.
The Russian-installed head of the eastern Donetsk region said “heavy shelling” by Ukrainian forces had injured 13 people on Monday.
“I am proud of every Ukrainian warrior. As long as you stand, Ukraine stands. I know how courageously and heroically you defend us,” Mr Zelenskyy said in his address.
Mr Putin made only a passing reference to the war in his address from the Kremlin marking the start of 2024, an election year in Russia.
“To everyone who is at a combat post, at the forefront of the fight for truth and justice: You are our heroes, our hearts are with you. We are proud of you, we admire your courage,” he said.
He said Russia had “proven more than once that we can solve the most difficult problems and will never retreat, because there is no force that can divide us”.
