Police are searching for a gunman who opened fire at a graduation party in Philadelphia, USA, Sunday night.

One person was killed and seven others were injured in the shooting, according to Philadelphia Police Commissioner Richard Ross, CNN wrote.

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Around 60 people were at the party when shots rang out, Ross said.

Ross said that four of the victims were teens between the age of 15 to 17 who suffered gunshot wounds to their legs.

An adult victim died of their injuries while three other adult victims in their twenties suffered various wounds to different parts of their bodies, Ross said.

Ross says it's not clear how many shooters were involved and a motive for the shooting is not yet known.