An off-duty California Highway Patrol officer was attacked and rendered unconscious last week by a group of teens after he came to the aid of a woman whose cellphone had been stolen, according to the Emeryville Police Department.

At about 8 p.m. Friday, the off-duty CHP officer saw the woman being assaulted by the group of juveniles on Bay Street and intervened, police said. The woman had returned to the scene where her cellphone had been stolen and demanded the teens return it, after which the group began to assault her.

After the off-duty CHP officer intervened, the teens became aggressive with him, striking him multiple times and choking him unconscious, police said. The officer regained consciousness and pepper-sprayed one suspect who was still attacking him.

Emeryville officers responded to the scene and detained several juveniles. Two of the teens, ages 14 and 16, were arrested, police said.

No further details were available.