A police officer has been sexually assaulted as she tried to arrest a man on suspicion of attempted rape.
She was one of two officers who came under attack in Sheffield city centre in the early hours of Friday morning.
South Yorkshire Police said they had responded to a report of an attempted rape on Scotland Street.
The suspect is said to have struck both officers with a wooden "for sale" sign, before sexually assaulting one of them as she tried to arrest him.
One of the officers was left with severe bruising, while both involved in the attack are said to be recovering at home.
A man is in police custody after he was arrested on suspicion of attempted rape, assault, sexual assault and criminal damage.
The female victim was treated for her injuries and is being supported by specially trained officers, while detectives are investigating the original incident.
Chief Inspector Lydia Lynskey said on Friday: "Our officers potentially face danger every time they respond to an incident, putting themselves in harm's way to serve and protect the communities of South Yorkshire.
"The officers who attended this morning were faced with a dangerous and violent situation, however they showed immense bravery in dealing with the incident.
"Our thoughts are with them and full welfare support has been put in place. We will always take a zero tolerance approach to assaults on our officers in the course of their duties."