KYIV: The war in Ukraine could last for years, the head of NATO said on Sunday, calling for steadfast support from Ukraine’s allies as Russian forces battle for territory in the country’s east.

Secretary-General Jens Stoltenberg said supplying state-of-the-art weaponry to Ukrainian troops would boost the chance of freeing its eastern region of Donbas from Russian control, Germany’s Bild am Sonntag newspaper reported.

After failing to take the capital Kyiv early on in the war, Russian forces have focused efforts on trying to take complete control of the Donbas, parts of which were already held by Russian-backed separatists before the Feb. 24 invasion.

“We must prepare for the fact that it could take years. We must not let up in supporting Ukraine,” Stoltenberg was quoted as saying.

“Even if the costs are high, not only for military support, also because of rising energy and food prices.”

British Prime Minister Boris Johnson, who visited Kyiv on Friday with an offer of training for Ukrainian forces, also said on Saturday it was important Britain provide support for the long haul, warning of a risk of “Ukraine fatigue” as the war drags on.

In an opinion piece in London’s Sunday Times, Johnson said this meant ensuring “Ukraine receives weapons, equipment, ammunition and training more rapidly than the invader”.

Ukrainian President Volodymyr Zelenskiy, who has rallied citizens with daily filmed messages, said he had visited forces in the southern Mykolaiv region, about 550 km (340 miles) south of Kyiv.

“Their mood is assured: they all do not doubt our victory,” he said in a video on Sunday that appeared to have been recorded on a moving train. “We will not give the south to anyone, and all that is ours we will take back.”

In Mykolaiv and Odesa regions, Zelenskiy said he had heard reports on destruction from Russian strikes.

“The losses are significant. Many houses have been destroyed; civilian logistics have been disrupted,” he said.

BATTLE FOR SIEVIERODONETSK

A top target in Moscow’s offensive to seize full control of Luhansk region - one of the two provinces making up the Donbas - is the industrial city of Sievierodonetsk, where the Ukrainian military said fighting and shelling continued.

“All Russian claims that they control the town are a lie. They control the main part of the town, but not the whole town,” Luhansk Governor Serhiy Gaidai told Ukrainian television, adding that fighting made evacuations from the city impossible.

Russia’s defence ministry said it had taken control of Metyolkine, just southeast of Sievierodonetsk, with Russian state news agency TASS reporting that many Ukrainian fighters had surrendered there. Ukraine’s military said Russia had “partial success” in the area.

Analysts at the Institute for the Study of War, a Washington-based think tank, wrote in a note that “Russian forces will likely be able to seize Sievierodonetsk in the coming weeks, but at the cost of concentrating most of their available forces in this small area”.

In Sievierodonetsk’s twin city of Lysychansk, residential buildings and private houses had been destroyed, Gaidai said. “People are dying on the streets and in bomb shelters,” he added.

In Ukraine’s second largest city Kharkiv, northwest of Luhansk, Russia’s defence ministry said its Iskander missiles had destroyed weaponry recently supplied by Western countries.

Russian forces were trying to approach Kharkiv, which experienced intense shelling in the first two months of the war, and turn it into a “frontline city”, a Ukrainian interior ministry official said.

West of Donbas, Russian missiles hit a fuel storage depot in Novomoskovsk, killing two people and injuring 13, the regional administration chief said. Video verified by Reuters showed thick black smoke rising into the air.

To the south, Western weaponry had helped Ukrainian forces advance 10 km (6 miles) towards Russian-occupied Melitopol, its mayor said in a video posted on Telegram from outside the city.

Reuters could not independently confirm the battlefield accounts.

Russia has said it launched what it calls a “special military operation” to disarm its neighbour and protect Russian speakers there from dangerous nationalists. Kyiv and its allies dismissed that as a baseless pretext for a war of aggression.

Ukraine received a significant boost on Friday when the European Commission recommended it for candidate status, a decision EU nations are expected to endorse at a summit this week. Actual membership could take years.