Police in the Pakistani city of Quetta have arrested at least 14 people in connection with Friday's bomb explosion that killed 11 people.
The device was fitted to a bicycle in a busy market area.
Two soldiers also died. A little known group, the Balochistan Liberation Army, says it carried out the attack.
There have been a series of bomb explosions in Quetta and other parts of Balochistan, where security has deteriorated over the past year.
The Balochistan Liberation Army is fighting against what is sees as the dominating influence of Punjabis on political life.
The group spokesman, Azad Baluch, told the BBC it had targeted a military truck "to express our anger".
He expressed regret for the civilian casualties.
Deteriorating security
Pakistan's President Pervez Musharraf condemned the attack and his
Information Minister, Sheikh Rashid Ahmed, said: "The people responsible will not go unpunished."
Friday's blast was the fifth recent bomb attack in Quetta involving bicycles.
The chief minister of Balochistan said the authorities were considering whether to register all bicycles in Quetta.
The BBC's Aamer Ahmed Khan in Karachi says there have been more than 30 bomb attacks in Quetta in the past year, but none have been as deadly as Friday's blast.
Quetta has also experienced sectarian violence.
In March, more than 40 Shia Muslims died when Sunni Muslim gunmen fired on a procession.
Quetta has also been a centre of operations for Pakistani security forces tracking al-Qaeda members.
In September they arrested an alleged senior al-Qaeda operative, Sharif ul Misri.