Hours earlier a powerful bomb ripped through the wall of a police station in the same town without causing any injuries, local police chief Salim Lehri said.
In another rail blast a passenger train escaped a possible accident when a pilot engine found part of the track missing at Dera Ghazi Khan, 90 kilometres west of Multan, in Punjab province.
A four-feet stretch had been blown up by a bomb leaving a two-feet deep crater and halting the Chiltan Express travelling from Quetta to Rawalpindi, railway police said.
Authorities started running the pilot engines to check rail routes last month after a series of train bombings in Balochistan. All night services in the province were also halted in January.
In Kohlu, Balochistan some 340 kilometres south-east of Quetta, militants blew up two microwave telephone masts, officials said.
As security personnel escorted telephone officials to repair the damage they were hit by a landmine blast, leaving a low-ranking soldier seriously injured an official of the paramilitary Frontier Corps official in Quetta confirmed. Security sources said the injured man lost his foot in the blast.