Later, the banned Tehreek-i-Taliban Pakistan (TTP) claimed responsibility for the attack.
The attack came in less than two weeks after three Levies personnel were martyred and as many injured when their vehicle hit a landmine in Ziarat district.
Situated at a distance of 54km southeast of Quetta, Mastung has been a frequent site of deadly bombings targeting civilians.
According to various reports, in July 2018, At least 128 people, including politician Nawabzada Siraj Raisani, were martyred and more than 200 injured in a deadly suicide blast in Mastung.
The militant Islamic State claimed responsibility for the attack through its Amaq news agency. The attack is the deadliest since the 2014 carnage at Peshawar's Army Public School.
In May 2017, 28 people were killed and over 40 others injured in an explosion near a local seminary in Mastung, which targeted the convoy of then deputy chairman Senate Abdul Ghafoor Haideri.
In 2014, more than two dozen people were killed and several injured when a powerful explosion ripped through a bus carrying Shia pilgrims.
In 2012, 19 people were killed and 25 others injured after three passenger buses were struck by an explosion in Mastung's Dringarh area. A remotely-triggered bomb had hit a convoy of three buses and set one of them ablaze.