Authorities say Ukrainian police officers and broadcasts are returning to the southern city of Kherson following the withdrawal of Russian troops after more than eight months of occupation.

The chief of the National Police of Ukraine, Ihor Klymenko, said in a Facebook post on Saturday that some 200 officers were at work in the city, setting up checkpoints and documenting evidence of possible war crimes.

Police teams also were working to identify and neutralise unexploded ordnance, and one sapper was injured Saturday while demining an administrative building, Klymenko said.

Ukraine's communications watchdog said national TV and radio broadcasts had resumed in the city, and an adviser to Kherson's mayor said humanitarian aid and supplies had begun to arrive from the neighbouring Mykolaiv region.

Speaking on Ukrainian TV, the adviser, Roman Holovnya, described the situation in the city as a humanitarian catastrophe. He said the remaining residents lacked water, medicine, and food.

The chairman of Khersonoblenergo, the region's prewar power provider, said electricity was being returned to every settlement in the Kherson region immediately after the liberation and obtaining mandatory permission from the military.