Chinese actor Jiang Jinfu is transported from a police station in Tokyo on Friday. (AP/Kyodo photo)

TOKYO: Japanese police said on Friday they have arrested a Chinese actor on suspicion of assaulting his former girlfriend, causing her injuries.

Jiang Jinfu, 27, was detained on Wednesday when he turned himself in to a downtown Tokyo police station. Police already had an arrest warrant for him after the 25-year-old woman filed a complaint over the alleged assault, prompting an investigation.

According to police, Jiang allegedly beat her in the face, arms and shoulders on Oct 12, causing injuries that required a monthlong treatment. The couple lived together at his apartment at the time but then apparently broke up, police said.

Jiang admitted to hitting the woman, police said, describing it as domestic violence. Japanese media said he has been in Tokyo since April to study Japanese.

Hong Kong's South China Morning Post identified the woman as Japanese model Haruka Nakaura. She posted her own photos purportedly showing bruised cheeks and upper arms on Instagram.

Japanese police refused to identify the women, citing privacy.