Pakistani police have arrested 12 men in Quetta, the capital of Balochistan province, in relation to a bus bombing on Sunday, officials say.
Police arrested 12 men after raids in Quetta
At least 13 people were killed and 20 others injured, when a bomb exploded on a Lahore-bound passenger bus that was travelling through Kolpur town.
The men were arrested in late night and pre-dawn raids in Quetta, police say.
Balochistan has Pakistan's main gas reserves. It has seen rising violence between rebels and security forces.
The rebels are demanding greater control over natural resources.
Balochistan's Inspector General of Police, Chaudhry Mohammed Yaqub, told the BBC, that the men were arrested in Quetta after late night raids on Sunday and pre-dawn raids on Monday.
He said the detained men had previous records of being involved in militant activities in the troubled province, but so far there was no evidence directly linking them to Sunday's blast.
The bus was carrying 50 people and had been travelling from the provincial capital, Quetta, to the eastern city of Lahore.
"It was a fearsome and very large explosion... There was blood in the bus. I was hit by somebody's severed hand and I lost consciousness," Lal Mohammed, a passenger in the bus who suffered leg and chest injuries, told the Associated Press news agency.
The army launched a major crackdown in Balochistan against militants recently after rockets were fired during a visit by President Pervez Musharraf.