In the past, authorities have blamed such attacks on Baluch nationalists, who have fought against the government for decades to press for political autonomy and greater share of profits from the region's natural gas resources.
Baluch nationalists have also targeted government officials and infrastructure including gas pipeline and power pylons.
Decline in fighting
Such attacks were more frequent in early 2006, but dropped off after Pakistani forces killed Nawab Akbar Bugti, one of the main leaders, late last year.
Pervez Musharraf, Pakistan's president, has promised an amnesty, and vowed to hunt down those who refuse to surrender.
Baluch nationalist groups accuse the government of exploiting their resources without passing on the benefits to people of the province.
Gas fields in Baluchistan meet much of Pakistan's demand. Musharraf is ploughing money into Baluchistan's infrastructure to create more economic opportunities.