A Ukrainian soldier who was captured by Russian troops in Mariupol has described his harsh treatment under captivity.

A 25-year-old Ukrainian marine was fighting at the Azovstal steel plant in early April when he was taken prisoner. Intense battles continued in the city.

The man suffered a concussion and broke his pelvis, jaw and nose. He became blind in his left eye. He was brought to the Russian-controlled city of Novoazovsk in the Donetsk region. He said it was where he realized he was a prisoner.

Russians barely provided him medical treatment. He said they didn't even give him painkillers. He was monitored around the clock and "forced to listen to Russian propaganda" twice a day.

In late April, the man was released through a prisoner swap after 17 days in captivity. He is currently being treated in a hospital in Ukrainian-controlled territory.

He said, "Many of my friends are still in Russian captivity. They are Mariupol's defenders who bravely conducted their mission."

He asked people to remember them and help the families searching for them.

Russia's state-run news agency reported that more than 1,000 Ukrainian prisoners who surrendered in Mariupol in May have been transferred to Russia. The Ukrainian side is seeking a prisoner swap, but negotiations with Russia seemed to be locked in a stalemate.