A lawyer for a prominent Russian journalist detained on charges of drug dealing has filed a complaint with the country's top investigative body, saying police used violence against him while in custody.

Police have denied claims that Ivan Golunov was beaten after his Thursday arrest; his lawyers said he may have suffered a concussion and rib fractures. He was examined in a hospital on Saturday and found to have abrasions on his back and a bruise around one eye.

Later Saturday, a court released Golunov into house arrest.

Olga Dinze, a lawyer with the human rights group Agora, filed a statement with Russia's Investigative Committee saying Golunov was subjected to "unmotivated physical violence" by police, Agora head Pavel Chikov said Sunday in a post on the Telegram messaging service.