Ukrainian president admits his army lacks enough troops and has only 25% of the air defences it needs as Russia advances in the north-east. What we know on day 815

Ukraine’s president, Volodymyr Zelenskiy, has warned that Russia’s offensive in the north-eastern Kharkiv region this month may only be the “first wave” of several and Russian troops could aim for the city of Kharkiv. “We have to be sober and understand that they are going deeper into our territory. Not vice versa,” Zelenskiy said on Friday in an interview with AFP. Russian forces “want to attack” the city, one of Ukraine’s largest, although they realise it would be “very difficult”, he added.

Zelenskiy said the situation in the region, where Russia has seized several border villages, was “controlled” but “not stabilised” after Ukraine sent reinforcements. The president said Russian troops had penetrated 5-10km along the north-eastern border before being stopped by Ukrainian forces.

Russia hit Kharkiv with more strikes on Friday that killed at least three people and injured 28, the city’s mayor, Igor Terekhov said. The Kharkiv regional governor, Oleg Synegubov, said Russian forces were trying to surround Vovchansk, an almost deserted town near the border. Russian strikes in Vovchansk killed one man.

Moscow expanded the area of active combat by almost 70km by launching its offensive in the Kharkiv region, Ukraine’s army chief, Oleksandr Syrskyi, has said. Syrskyi said Russia launched the offensive to force Ukraine to throw additional reserve brigades into fighting. He added that he expected fighting to intensify as troops are also preparing to defend in northern region of Sumy.

Vladimir Putin said Russian forces advancing in the Kharkiv region were creating a “buffer zone” to protect Russian border regions, but said capturing the city of Kharkiv was not part of Moscow’s current plan. The Russian president, who made the comments at a news conference during a state visit to China, said the recent thrust into the Kharkiv region was a response to Ukrainian shelling of Russian border regions such as Belgorod.

A Ukrainian drone attack killed one person and injured another in the Belgorod region, the regional governor, Vyacheslav Gladkov, said on Friday. Russia’s defence ministry later reported that air defence units had intercepted and destroyed 14 multiple-launch rockets originating in Ukraine. A massive Ukrainian drone attack on Crimea early on Friday caused power cutoffs in the city of Sevastopol and set a refinery ablaze in southern Russia.

Zelenskiy has admitted Ukraine’s army needs more troops to boost the forces’ morale. “We need to staff the reserves … A large number of [brigades] are empty,” the president said. Many Ukrainian soldiers have been fighting for more than two years without the possibility to be discharged. The army is struggling to recruit, while fighters are growing exhausted and angry at the lack of rotation. “We need to do this so that the guys have a normal rotation. Then their morale will be improved,” Zelenskiy said.

Ukraine only has a quarter of the air defences it needs, Zelenskiy has said, and called for more than a hundred aircraft to counter Russian air power. “So that Russia does not have air superiority, our fleet should have 120 to 130 modern aircraft … to defend the sky against 300 [Russian] aircraft,” he said.

Putin is seeking to weaponise the threat of mass migration to divide and weaken Europe, the Estonian prime minister, Kaja Kallas, said on Friday. “What our adversaries know is migration is our vulnerability,” she said. “The aim is to make life really impossible in Ukraine so that there would be migration pressure to Europe, and this is what they are doing.” Kallas conceded that some countries in Europe did not see the threat of a Ukrainian defeat in the same way. “They don’t see and they don’t believe that if Ukraine falls Europe is in danger, the whole of Europe, maybe some countries, but not the whole of Europe.”