FOUR men are being questioned by police following reports of a serious sexual assault on a 26-year-old man in Oxford today.

Police cordoned off an alleyway in Frideswide Square, opposite the Said Business School, at about 5.30am.

An investigation was launched and a forensics team had scoured the area, while officers were standing guard on the cordon.

A police spokesman said four men - all aged in their early twenties - were in custody.