A remotely-detonated bomb killed three workers doing a survey for a local oil exploration company in Dera Bugti on Tuesday.
Local police official Mohammad Hussain said the bombing near the town of Dera Bugti also wounded five surveyors.
According to Levies force, it was a landmine explosion which happened in area of Toba-No-Haqani in Dera Bugti. It resulted in death of three people including a labourer. Six people are reported injured in this incident.
Blast was targeted at workers of the company situated at Toba-No-Haqani. Levies forces reached the site of incident and shifted bodies and injured to the nearby hospital, where they were provided medical assistance.
There was no immediate claim of responsibility, but small nationalist groups and separatists have claimed previous such attacks in the province. Militants also have a strong presence in Balochistan.
The latest violence came a day after assailants ambushed a convoy of paramilitary troops, killing six of them in the Awaran district. No group has claimed that attack either.
In a separate incident on Tuesday, a grenade was thrown at the election office of a candidate running for a seat in parliament, wounding 10 people, according to Ayaz Khan, an assistant commissioner in the town of Ramzak, in the northwest near the Afghan border.
He said the candidate, Aurang Zeb, who is from the party of former cricket star Imran Khan, was not present at the time of the attack. It was the first violent incident ahead of the July 25 vote.
