Ukraine on Monday said Russia had launched a “record” number of 90 drones in attacks on New Year’s Eve that killed several people and left dozens injured.

Most of the drones involved were downed by its air defences, Ukraine said on New Year’s Day, days after Moscow’s deadliest strikes on Ukrainian cities in nearly two years of war.

The mounting attacks and casualties came as both sides settle in for a protracted war after Russia’s full-scale invasion launched in February 2022 failed to achieve its aims but claimed hundreds of thousands of casualties on both sides.

Ukraine’s air force said on Sunday that “the whole of Ukraine is on missile strike alert” after Russian MiG-31 jets had taken off, with “significant activity” recorded in the east and south of the country.

Ukrainian officials reported Russian artillery and air strikes in regions across the country, including the southern city of Kherson liberated in autumn 2022, where a 14-year old boy was killed and another child and two women were seriously injured.

In other regions, despite Russian claims of targeting military infrastructure, Ukrainian officials reported strikes on power lines, grain storage facilities, pharmacies and office buildings.

In Kharkiv region, police said Russian artillery strikes had killed a woman and two men in the village of Borova on Saturday night. The region’s governor Oleg Synegubov said at least six missiles had hit Kharkiv city, with 28 civilians injured in strikes that also hit healthcare buildings and the prominent Kharkiv Palace hotel which is frequented by media.

Ihor Klymenko, Ukraine’s minister for internal affairs, said a journalist from the UK was among those injured in the attack. A German team from public broadcaster ZDF was also in the hotel at the time of the attack and their translator suffered spinal injuries, the TV network said.

“On the eve of the New Year, the Russians want to intimidate our city, but we are not scared,” Ihor Terekhov, Kharkiv’s mayor, said in a statement on social media. His posts included photos and videos of rescue workers putting out fires and searching through rubble for survivors at bombed-out residential buildings, a café and a bank.

Moscow on Sunday described the Kharkiv attack as retaliation for Ukraine’s alleged attack a day earlier which it said had killed more than 20 people in Russia’s city of Belgorod, just a few kilometres north of the Ukrainian border.

The Kharkiv and Belgorod attacks came after record Russian missile and drone strikes hitting targets across Ukraine on Friday claimed nearly 50 lives, including 23 in Kyiv.

“In retaliation to this terrorist attack, the Armed Forces of the Russian Federation struck the decision-making centres and military targets in the city of Kharkiv,” Russia’s defence ministry said Sunday.

The ministry claimed that troops from Ukraine’s army and GRU military intelligence unit “directly involved in planning and executing the terrorist attack in Belgorod . . . were neutralised by a precision-guided missile strike at the former Kharkiv Palace hotel complex”.

“Up to 200 foreign mercenaries who were . . . involved in terrorist raids on the territory of the Russian Federation bordering on Ukraine were also there,” the ministry said, pointing to units of Russian citizens fighting on Ukraine’s side which have routinely conducted raids cross-border attacks in the region.

Ukraine’s GRU military intelligence service denied these claims.

Ukrainian media, citing domestic intelligence sources, reported that the explosions in Belgorod were caused by debris from projectiles falling upon the city after being “unprofessionally” intercepted by Russian air defences.

In a Saturday address to the nation, Ukrainian President Volodymyr Zelenskyy said the Russian attack had affected “more than 120 of our cities and villages” and pledged retaliation.

“For every ‘Shahed’ drone, for every Russian missile, there will be a fair responsibility of the terrorist state. Both political and very practical,” he said.

Without directly referring to delayed decisions by the US and EU to approve financial and military assistance for 2024, Zelenskyy said he had discussed with his military chiefs what still needed to be done next year.

“Despite everything that will happen in other countries, despite any political changes and moods, we need sufficient potential to do our own thing,” Zelenskyy said, adding that Ukraine was preparing for increased weapons production in 2024.

In a separate year-end address, Zelenskyy mentioned his forces’ stepped-up long-range strikes on Crimea, the Ukrainian peninsula occupied by Russia since 2014, which forced the Russian navy to withdraw to eastern parts of the Black Sea. This, in turn, allowed Kyiv to break Moscow’s blockade of its ports by unilaterally restarting maritime exports of grain, metals and other commodities.

A long-anticipated counteroffensive this year failed to make significant territorial gains, despite modern weaponry supplied by Kyiv’s western allies. Russia has also failed to win any major land offensive this year, though it continues to occupy about 18 per cent of Ukrainian territory.

Zelenskyy highlighted the positives: “This year, Ukraine did not retreat in any direction on earth, regained the sea and made the sky safer.”