Detectives in Derry say they are treating last nights shooting in the Waterside area as attempted murder.
A man in his 30s is recovering in hospital after sustaining an injury to his foot after two masked men entered the property on Margaret Street.
During the incident a 58 year old man was also shot at but was uninjured.
Police believe the suspects may have fled the scene in a car.
The gunman is described as being of medium to heavy build, and had his face covered while the second masked man is said to have been of a thinner build.
There were three other occupants in the house at the time of the shooting.
Detective Inspector Michael Winters says they are working to establish a motive for what he has described as a merciless attack.
He is appealing to anyone who was in Margaret Street between 8:40pm and 8:50pm last night and saw anything believed to be connected to what happened - any suspicious vehicles, or people acting suspiciously to contact detectives at Strand Road on 101 quoting reference number 1838 08/10/19 or Crimestoppers on 0800 555 111.