Russian President Vladimir Putin has promised to intensify strikes on Ukraine after an unprecedented attack on the Russian city of Belgorod over the weekend.

Saturday’s air attack killed at least 25 people and wounded more than 100, according to Russian officials.

Russia has blamed Ukraine for the attack, which was one of the deadliest to take place on Russian soil since Moscow’s full-scale invasion of Ukraine started more than 22 months ago.

“We’re going to intensify the strikes. No crime against civilians will rest unpunished – that’s for certain,” Putin said on Monday during a visit to a military hospital.

He said Russia would continue hitting what he called “military installations”.

“We are doing that today, and tomorrow, we will continue doing it,” Putin said.

Putin previously called the destruction in Belgorod a “terrorist attack” and accused Ukrainian forces of targeting “the city centre, where people were walking before New Year’s Eve”.

He said Ukraine was being used by the West to “settle its problems” and insisted the course of the war was changing in Russia’s favour.

The Russian Ministry of Defence said Ukraine hit Belgorod with two missiles and several rockets. It said most of the weapons were shot down, but some debris fell on the city.

Vyacheslav Gladkov, governor of the Belgorod region, said the attack damaged 30 apartment buildings and several houses and cars.

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Ukrainian officials rarely acknowledge responsibility for attacks on Russian territory.

New Year’s Day attacks

At least five people were killed in New Year’s Day attacks on southern Ukraine’s Odesa region and the Russian-occupied eastern city of Donetsk.

A 15-year-old boy was killed and seven people were wounded when falling debris from one of 87 downed drones hit a residential building in the southern Ukrainian city of Odesa, the head of the region’s military administration, Oleh Kiper, said.

In the western city of Lviv, Russian attacks severely damaged a museum dedicated to Roman Shukhevych, a Ukrainian nationalist and military commander who fought for Ukrainian independence during World War II. University buildings in the town of Dubliany were also damaged.

Writing on social media, Lviv Mayor Andriy Sadovyi described the strike as “symbolic and cynical”, adding, “This is a war for our history.”

Four people were killed and 13 wounded in Ukrainian shelling of Russian-occupied areas of Donetsk, according to the region’s Kremlin-installed leader, Denis Pushilin. Russian state media reported that a journalist was among the victims but provided no details.

One person was also killed and another wounded in shelling on the Russian border town of Shebekino, Governor Vyacheslav Gladkov said.