Ukraine will be able to win the war in 2023 if it receives more Western weapons, particularly long-range missiles and heavy tanks, Ukrainian presidential adviser Mykhaylo Podolyak told AFP Wednesday.
Otherwise, the war will grind on "for decades", Podolyak said, pointing out that the "bloodiest" fighting was currently taking place in eastern Ukraine in Bakhmut and Soledar.
"Only missiles with a range of more than 100 kilometres (60 miles) will allow us to significantly accelerate the de-occupation of our territories," he told AFP in an interview.
The United States last year supplied Ukraine with missile systems with a range of around 80 kilometres that were credited with turning the tide of the conflict in Kyiv's favour on several fronts.
Kyiv has also recently received similar French systems.
But it is putting pressure on Washington to deliver US ATACMS missiles, which boast a range of around 300 kilometres.
These systems would allow Ukrainian forces to target Russian arms depots deep inside Ukrainian territory controlled by Moscow but currently out of range of the weapons in Kyiv's arsenal.
Ukraine could "destroy all Russian military infrastructure in occupied territories, including in Donbas" in east Ukraine and in Crimea, the Black Sea peninsula annexed by Moscow in 2014, said Podolyak.
- 'Defensive war' -
But the United States have been hesitant to offer long-range missile capacities to Ukraine, fearing an escalation that would pit the United States more directly against Russia.
"We will not attack Russia," the senior advisor said. "We are waging an exclusively defensive war."
Europe and the United States may soon speed up deliveries because they understand these supplies are key to "limit this war to the occupied territories" and end it, he added.
Ukraine also needed armour, in particular heavy tanks, such as German Leopards and artillery, said Podolyak.
"France is already delivering light tanks to us. That's very good. But we still want to get 250 to 300 to 350 heavy tanks," he added.
Polish President Andrzej Duda announced later that Poland was ready to send Leopard tanks to Ukraine that Kyiv requested, but as part of an international coalition.
Kyiv's other priority needs are more 155-millimetre calibre shells, combat drones capable of carrying out deep attacks inside occupied territories and anti-aircraft systems -- including German Cheetah anti-aircraft armoured vehicles, said Podolyak.
New anti-aircraft defence systems, like US Patriots or the French Crotale will soon be able to neutralise the threat posed by Russian bombing campaigns against Ukrainian energy installations, he said.
"We will be able to close our skies in the space of a month," he said.
Ukraine would soon be able to shoot down 95 percent of missiles fired by Russia, instead of 75 percent currently, he said.
- 'Bloodiest' fighting -
Meanwhile the "bloodiest" scenes are happening in Bakhmut, an urban hub in the eastern Donbas region that Russia has been trying to seize for months, as well as in the neighbouring town of Soledar.
Podolyak said Russia had deployed its best army units as well as the Wagner fighting group for the battle.
"There's a lot of blood, a lot of artillery duelling, a lot of close contact fighting, especially today in Soledar," Podolyak added.
He described the area as the "hottest spot in the war" and talked of "extraordinary" losses on the Russian side and "significant" losses for Ukraine.
Unlike previous urban battles in Ukraine, few civilians remain near the embattled towns of Bakhmut and Soledar.
The siege of the port city of Mariupol in the first months of the war cost thousands of Ukrainian lives, Kyiv has said.
"If in Mariupol 90 percent of deaths were civilians, in Soledar and Bakhmut it's soldiers," he said.
On Wednesday paramilitary group Wagner claimed to control Soledar, but the Russian defence ministry quickly poured water over the claim.
Its fall would mark Russia's first significant territorial gains in Ukraine in months.
But even a victory there would "not make any sense" strategically for Russia, Podolyak said.
"For us, it's a bridgehead to advance towards Donetsk," Podolyak said, referring to the main city and pro-Russian separatist stronghold in the eponymous Donetsk region of eastern Ukraine.
"But for the Russians, there is no strategic goal. It is an open space, and our positions are more advantageous," Podolyak said.
"We see a completely irresponsible attitude -- to put it mildly -- from the Russian elite towards their own military personnel, who are dying there by the thousands," Podolyak said.