Russian forces have been stepping up attacks on the southern Ukrainian city of Kherson as Saturday marked one year since its liberation from Russian occupation.

Regional governor of Kherson Oleksandr Prokudin said the city was shelled numerous times from Saturday to Sunday morning, killing a 64-year-old man and wounding four others. He also said a library was damaged.

A Ukrainian commander who leads troops fighting in the south posted on social media on Sunday that Russian forces were ramping up airstrikes using guided bombs. He wrote that Russian troops had launched 30 airstrikes on a southern city over the previous day.

Ukraine's intelligence agency said the Ukrainian side is responsible for a blast that killed at least three officers in Melitopol, a major city in the southern region of Zaporizhzhia on Saturday.

The agency called the explosion an act of revenge carried out by representatives of the local resistance movement. It also said the strike was carried out during a meeting attended by members of a Russian security agency and others.

Local authorities on the Russian side did not acknowledge the attack. They said on social media that a car caught fire due to a mechanical problem and that no one was injured.

Ukraine's military officer said Ukrainian forces will continue its counteroffensive in and near Melitopol.