Russia's invasion of Ukraine is "losing momentum" as it withdraws from the second-largest city, with a top Nato diplomat now predicting President Volodymyr Zelenskyy's forces "can win this war".
The UK Ministry of Defence says Vladimir Putin is "likely" to have lost "one-third" of the ground forces he committed to the invasion and Russia has "failed" to achieve any "substantial territorial gains" in the past month.
"Russian forces are increasingly constrained by degraded enabling capabilities, continued low morale, and reduced combat effectiveness," the MoD said.
"Russia is unlikely to dramatically accelerate its rate of advance over the next 30 days."
But as Russians pull back from Kharkiv there has been sustained mortar, artillery and airstrike attacks at the eastern Donetsk province. These tactics that have been employed to "deplete Ukrainian forces and destroy fortifications", according to Ukraine's general staff.
The United States' Institute for the Study of War has said that Ukraine "appears to have won the Battle of Kharkiv" following the withdrawal of Russian troops in the area.
“The brutal invasion (by) Russia is losing momentum,” Nato Deputy-Secretary General Mircea Geoana told reporters. “We know that with the bravery of the Ukrainian people and army, and with our help, Ukraine can win this war.”
He is in Berlin along with other Nato leaders on Sunday, including UK Foreign Secretary Liz Truss, to discuss providing further support to Ukraine and moves by Finland, Sweden and others to join the western military alliance.
Ms Truss said security in Europe will be strengthened if Finland and Sweden apply to join, as expected.
“Putin must face a sustained defeat in Ukraine, Russia must be contained and such aggression must never happen again,” she said.
Ms Truss said the meeting had agreed that they must continue to support Ukraine to help it to “push Russia out”.
“Ukraine’s security must come from it being able to defend itself. Allies must support Ukraine’s move to Nato-standard equipment, immediately providing artillery, training and the required expertise.”
Ukraine defence minister Oleksii Reznikov said the war is now “entering a new - long-term - phase".
President Volodymyr Zelenskyy added Ukrainians were doing their “maximum” to drive out the invaders, stating the outcome of the war would depend on support from Europe and other allies.
“No one today can predict how long this war will last,” Mr Zelenskyy said in his nightly video address late on Friday.
After Russian forces failed to capture Kyiv following the February 24 invasion, Mr Putin shifted his focus eastward to the Donbas, an industrial region where Ukrainian troops have battled Moscow-backed separatists since 2014.
Russia's offensive aims to encircle Ukraine's most experienced and best-equipped troops, who are based in the east, and to seize parts of the Donbas that remain in Ukraine's control.
As airstrikes and artillery barrages batter the region, the battle appears to be a back-and-forth slog with no major breakthroughs on either side.
Fighting for Kharkiv
Kharkiv, which is not far from the Russian border and only 50 miles southwest of the Russian city of Belgorod, has undergone weeks of intense shelling.
The largely Russian-speaking city with a pre-war population of 1.4 million was a key Russian military objective earlier in the the war, when Moscow hoped to capture and hold major Ukrainian cities.
Regional governor Oleh Sinegubov said in a post on the Telegram messaging app that there had been no shelling attacks on Kharkiv in the past day.
Mr Zelenskyy said in his nightly video address to the nation that Ukrainians were doing everything they could to drive out the Russians, but “no one today can predict how long this war will last”.
“This will depend, unfortunately, not only on our people, who are already giving their maximum,” he said. “This will depend on our partners, on European countries, on the entire free world.”
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Mr Zelenskyy also warned that the war is causing a food crisis around the world due to a Russian blockade stopping Ukrainian grain from leaving port.
The G7 echoed that warning, saying that: “Russia’s war of aggression has generated one of the most severe food and energy crises in recent history, which now threatens those most vulnerable across the globe”.
Russian president Vladimir Putin had launched the war in Ukraine to thwart NATO’s expansion in Eastern Europe.
But the invasion of Ukraine has other countries along Russia’s flank worried they could be next.
This week, the president and prime minister of Finland said they favoured their country seeking Nato membership.
Officials in Sweden are expected to announce a decision Sunday on whether to apply to join the Western military alliance.
Russia warned that if Finland and Sweden join Nato, the decision would instantly turn them from neutral into hostile countries and potential targets for Russia.Putin told Finnish President Sauli Niinistö that there are no threats to Finland’s security and joining NATO would be an “error” that would “negatively affect Russian-Finnish relations”.
The Kremlin said the two leaders had a “frank exchange of views” in a phone call on Saturday.
Mr Niinistö said the discussion “was straightforward and unambiguous and was held without exaggeration. Avoiding tensions was considered important”.