A rare humanitarian ceasefire in Ukraine’s front-line Kherson region that allowed civilians to evacuate the Russian-occupied city of Oleshky has ended.

The localised ceasefire was due to end at 22:59 Ukrainian time (21:00 GMT) on Sunday. While the truce had held since it was implemented last week, fighting had continued elsewhere.

On Sunday evening, Ukraine’s air alert system was apparently hacked, the country’s air force said, warning of radiation over Kyiv – a reference to a possible nuclear attack.

The Air Force message read: “The Air Alarm application has probably been subjected to hostile interference. There is no radiation threat! Stay calm and follow our updates on our channel.”

Ukrainian President Volodymyr Zelensky said Russia had struck energy infrastructure in four regions overnight on Saturday, leaving hundreds of thousands of homes without power. Some connections were restored on Sunday.

Another overnight strike killed two people, including a 13-year-old girl, in the Vinnytsia region, the State Emergency Service of Ukraine said.

Meanwhile, Ukraine hit a major missile fuel producer in Russia’s Rostov region, which caused a fire and damaged four production facilities, Zelensky said.

In Ukraine, repair works to restore power continued throughout the day. Most customers in the Dnipropetrovsk region had their connections restored by early evening, but more than 60,000 were still without power, the governor said.

Because of regular attacks on energy infrastructure, emergency power cuts have been introduced across the country. Even in the capital Kyiv, electricity is cut off for most of the day, and water supplies are also disrupted.

Zelensky said in a social media post that the intensity of Russian strikes has been “extremely high” over the past week, adding that Russia was “trying to take maximum advantage of the shortage of ballistic missile interceptors”.

He added that “every day” Ukraine communicated its need for Patriot missiles – the only effective weapon for downing Russia’s deadly ballistic missiles – to the US, Europe and other partners. He thanked countries for their support so far and longer-term commitments, but called again for more immediate aid.

The limited pause in hostilities, which started on Tuesday, was brokered with the help of US First Lady Melania Trump and Pope Leo.

It was originally confined to the city of Oleshky, which has been occupied by Russia since the first days of Russia’s full-scale invasion of Ukraine in February 2022, and was expanded across the wider region of Kherson.

Oleshky had been trapped on one side by the Dnipro river and the other by Russian forces, with routes out mined and subject to drone attack.

Residents trapped there were suffering severe shortages of food, water and electricity, with many resorting to cooking garden weeds to survive.

The truce allowed for Oleskhy residents to evacuate if they wanted, and there were emotional scenes on Saturday of reunions between loved ones who hadn’t seen eachother for years.

There are Ukrainian military positions just 5km (3.1 miles) from Oleshky, but evacuees had to travel through Russian-occupied territory to southern Russia, where they flew to Belarus, before finally being driven across Ukraine’s northern border.

The oldest evacuee was 94 years old, while the youngest was one, according to Dmytro Lubinets, Ukraine’s human rights ombudsman.