A gang of men forced their way into a house and attacked the woman and girl inside with machetes yesterday.
The teenage girl, 13, suffered serious stab wounds and is in a critical but stable condition in hospital.
A woman, 41, was also treated for stab wounds but has since been discharged from hospital.
The men attacked them with a baby present at the scene, which was not harmed.
The PSNI said the gang broke into the property on Trasna Way in Lisnaskea, Co Fermanagh, at around 9.15pm.
PSNI Detective Sergeant Keith Monaghan said: ‘This must have been a terrifying ordeal for those involved and we are determined to find the men responsible.
‘We have several lines of enquiry which we are progressing at this time but I would ask anyone with information or who noticed any suspicious activity in the area to contact detectives in Enniskillen and pass that information on.’
Alliance Fermanagh representative Matthew Beaumont said whoever carried out an attack in Lisnaskea needs to be caught quickly.
He said: ‘This attack in Lisnaskea, carried out by men carrying machetes, is to be condemned in the strongest possible terms.
‘Whoever was responsible for this horrific attack must be caught quickly and face justice.’
‘I hope the two females injured make a full and speedy recovery. This must have been a terrifying experience for them.’