Ukraine's biggest cities targeted in strikes as Kyiv's air force says 21 Russian drones were destroyed
Russia has launched fresh airstrikes on Ukraine, hours after Moscow accused Kyiv of attacking a Russian city close to the border.
The strike in Belgorod killed at least 24 people and injured 108 - making it one of the deadliest attacks on Russian soil since the start of Moscow's invasion of Ukraine 22 months ago.
Russia called it a "terrorist attack" and said it would not "go unpunished".
Russian drones targeted civilian, military and infrastructure in the Kharkiv, Kherson, Mykolaiv and Zaporizhzhia regions, the air force said.
Kharkiv, Ukraine's second-largest city, was pounded with missiles and drones in the hours leading into New Year's Eve.
Russia Defence Ministry said the strikes had attacked "decision-making centres" and military facilities in the city.
A drone attack hit several residential buildings, causing fires, Kharkiv's mayor Ihor Terekhov said.
"On the eve of the New Year, the Russians want to intimidate our city, but we are not scared - we are unbreakable and invincible," Mr Terekhov said on Telegram.
He posted several photos showing windows blown out of residential buildings and firefighters putting out a fire at what seemed like a store.
Kyiv's air force has said the Ukrainian military destroyed 21 out of 49 attack drones launched by Russia overnight.
The last week of 2023 has seen increased attacks by both sides.
On Saturday, Russia's foreign ministry requested a United Nations Security Council meeting to discuss what officials have called the "indiscriminate" shelling of Belgorod, according to the state-run news agency RIA.
"The terrorist attack in Belgorod will be the subject of proceedings in the UN Security Council," foreign ministry spokeswoman Maria Zakharova is reported to have said.
In a posting on Telegram on Sunday, Belgorod's governor Vyacheslav Gladkov said the number of dead in the shelling had risen from 21 to 24.
He added that 108 were wounded after Saturday's attack, which he said had damaged 37 apartment buildings among other locations.
Russia's Defence Ministry said in a statement on Sunday: "This crime will not go unpunished."
While Kyiv never acknowledges responsibility for attacks on Russian territory or the occupied Crimean Peninsula, larger aerial strikes against Russia have previously followed heavy assaults on Ukrainian cities.
Images of Belgorod on social media showed cars on fire and plumes of black smoke rising among damaged buildings as air raid sirens sounded.
One strike hit close to a public ice rink in the heart of the city.
Earlier on Saturday, officials in Russia reported shooting down 32 Ukrainian drones over the country's Moscow, Bryansk, Oryol and Kursk regions.
They also reported that cross-border shelling had killed two people in Russia - one man in the Belgorod area and a nine-year-old in the Bryansk region.
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Poland's defence forces said on Friday that an unknown object had entered the country's air space before vanishing from radars, and that all indications pointed to it being a Russian missile.
Poland's deputy foreign minister summoned Russian ambassador Andrei Ordash on Friday to discuss the alleged breach of Poland's airspace.
However, Mr Ordash said Poland had provided no proof of Russian involvement.
In a statement, published by the state-owned RIA news agency, Mr Ordash said: "I was handed a note which contained an unsubstantiated claim that allegedly on the morning of 29 December, an airborne object violated Polish airspace, which Polish specialists identified as a Russian guided missile.
"No proof was presented. My request for documented proof of what was in the note was refused."
