Protesters blocked key highways in a volatile southwestern province on Wednesday in unrest sparked by the killing of a top tribal chief in a weekend Pakistani army raid, officials said.
Police also announced that up to 700 people have been detained since riots erupted on Saturday after Nawab Akbar Bugti, a fugitive political and militia leader, was killed in his mountain hide-out.
Balochistan police chief Chaudhry Mohammed Yaqoob said scores of protesters have blocked two roads linking the provincial capital of Quetta to the southern port city of Karachi and one heading west to Iran.
Another key road linking Gawadar, a remote Balochistan town on the Arabian Sea coast, with Karachi, was also blocked by boulders and crudely erected barricades, Yaqoob said.
Bugti supporter Habib Jalib said angry Baluch tribesmen were blocking all roads into Balochistan in their continuing protest over the death of Bugti, who led an often violent campaign against government forces for greater control of natural resources extracted in this region.
"More than 70,000 of our supporters are active across Balochistan to record their protest against the killing of their beloved leader," said Jalib, a senior figure in the Baloch Solidarity movement, an alliance of four ethnic-Baloch political groups that ordered the highways blocked.
Police are in contact with Bugti supporters to try open the roads, officials said.
Police chief Yaqoob said between 650 and 700 people have been arrested during four days of violence that has seen scores of government buildings, businesses and vehicles burned.
Jalib said police have arrested 850 alliance supporters throughout Balochistan since Saturday. The difference in the numbers could not be immediately reconciled.
At least six people have been killed, including two during fiery protests and four in a Tuesday bombing at a roadside restaurant. It was unclear if the blast was linked to the Bugti protests.
There were no immediate reports of violence in Quetta on Wednesday, unlike a day earlier when angry protesters threw hand grenades at police and set fire to 20 businesses following a funeral service held for Bugti in a stadium attended by at least 10,000 people.