A bomb blast on a railway track in Pakistan's Balochistan region killed at least four people on Sunday and injured several others. 

The improvised explosive device (IED) detonated as the Quetta-Rawalpindi Jaffar Express passed through the Dasht area in Mastung district in Balochistan, which is said to be the most restive region in the troubled province. 

Pakistan's Dawn reported that four were killed while The Express Tribune has said there were three casualties. 

At least ten other passengers were injured in the bomb blast. 

The IED was loaded with 8 kilograms of explosives, according to the reports. No terror group has so far claimed responsibility. 

The Jaffar Express had been targeted by terrorists juste arlier this year, but the blast had not killed anyone.