Detectives said they are not looking for anyone else in the connection with the death of a four-year-old girl as her mother is questioned on suspicion of murder.
The 31-year-old woman walked into Manchester Royal Infirmary at around 7.15pm yesterday and "expressed concerns" about the welfare of her child to doctors and nurses.
Staff contacted police, who went to a house in Garthorne Close, Moss Side, about two miles from the hospital.
Officers discovered the child's body when they entered the two-storey property.
The cause of the girl's death has yet to be established as a post-mortem examination will be carried out later by a Home Office pathologist.
The child has not been formally identified and police are continuing to attempt to trace all her family members.
It emerged that there has been previous contact between the girl's family and police, and also other agencies.
Chief Superintendent Stuart Barton said: "This is clearly a tragic incident and I understand there will be a lot of shock and upset in the community following the death of a four-year-old girl.
"Our thoughts are with the girl's family at this extremely difficult time.
"We know there is lots of speculation about the identity of the young girl and the cause of death but I want to stress that, as yet, we have not formally identified her and we are doing a lot of work to try and trace all her family members to inform them.
"Similarly, the cause of death is also unknown at this stage and, until the results of the post-mortem, it would be inappropriate to comment further.
"However, what I can say is that, at this time, we are not looking for anyone else in connection with this incident and I want to try and reassure our community that there is no reason for them to be unduly alarmed, although clearly they will be upset at this tragedy.
"Greater Manchester Police, along with our partner agencies, is also aware of previous contact between ourselves and other agencies with the girl's family, and we will be conducting a multi-agency review.
"This is obviously a very distressing time for people, and our primary focus is to establish exactly what happened to this young girl.
"We have a dedicated team of detectives working alongside our local neighbourhood officers and I would ask them if anyone does have information, or any concerns, that they approach one of my officers or call police."
Anyone with information should call police on 0161 872 5050 or the independent charity Crimestoppers, anonymously, on 0800 555 111.