Three boys aged between 10 and 12 were killed in a blast at a religious seminary in the southern Pakistani city of Karachi on Monday

Three boys aged between 10 and 12 were killed in a blast at a religious seminary in the southern Pakistani city of Karachi on Monday, police said.
  
The attack occurred in the impoverished western district of Orangi.

A senior local police official, Javed Alam Odho told AFP that the police were trying to ascertain whether it was a planted bomb or a hand grenade that had been thrown.
  
A senior doctor at the Abbasi Shaheed hospital, Parshotum Rathore, confirmed the number of deaths and said those who died in the attack were between 10 and 12-years-old. He put the number of injured at more than 12 and said the condition of four of those hurt was critical.
  
Nobody has so far claimed responsibility for the attack.