A care assistant has been arrested on suspicion of attempted murder after a "serious incident" at a Liverpool hospital.
Merseyside Police said officers were contacted by staff at Broadgreen Hospital at 19:25 BST on 22 July and an investigation is under way.
A 31-year-old man has been arrested and released on conditional bail.
A hospital spokesman said there is "no suggestion" patients or their loved ones should be concerned over safety.
The hospital is investigating the "serious incident" and assisting police with their inquiries, the spokesman added.