ISLAMABAD, 6 February 2006 — At least 13 people were killed and 20 injured when a powerful bomb exploded on a passenger bus yesterday in the southwestern Balochistan province.

“Thirteen people were killed and 20injured in the explosion on the passenger bus,” Interior Minister Aftab Sherpao said.

The bus, which was carrying 50 passengers, was traveling through the Bolan Pass region on a regular run from the provincial capital Quetta to the eastern border city of Lahore in the Punjab province when the blast occurred. “It was a timing device planted inside the bus,” Balochistan police chief Chaudhry Yaqoob told reporters.

Yaqoob said the injured had been taken to a hospital in Quetta. No one has claimed responsibility for the attack.

Meanwhile, tribal militants fired more than 100 rockets into a town near the largest gas field in the troubled province, killing eight people, officials said yesterday.

The rockets hit the town of Sui late Saturday, damaging 16 houses. Police said two military guards and six civilians were killed in the attack, which followed a similar rocket blitz on Friday and early Saturday around the nearby town of Dera Bugti.

The area’s senior government administrator, Abdul Samad Lasi, said nine people were wounded in the attack on Sui, which he blamed on “miscreants,” a term officials use to describe Baloch militants battling for autonomy. Officials said the death toll could rise as a search for bodies was continuing.

Sui is the site of Pakistan’s main gas field and is about 720 km (450 miles) southwest of the capital Islamabad.

Lasi said the militants also blew up a section of gas pipeline and a water pipeline in a gas field in Dera Bugti overnight, while a land mine blast yesterday killed one civilian in the nearby Kohlu district.

Interior Minister Sherpao said security forces were currently limiting their activity to defensive action but warned that “this strategy can be changed for the protection of gas installation and local population.”

“Attacks on national installations cannot be tolerated,” he said in an interview on private Geo TV.

Baloch militants have been waging a low-key insurgency for decades seeking more autonomy and benefits from the oil and gas. They have intensified attacks in the past year. The latest violence came after President Pervez Musharraf on Friday demanded that Baloch tribal leaders disband their “private militias.”

The military launched a major crackdown on militants in Balochistan after a rocket attack on Dec. 14 during a visit by Musharraf to Kohlu. The crackdown coincided with the announcement of plans to privatize two gas distribution firms in Balochistan.

Baloch nationalists say hundreds of people have been killed. Analysts say this could be an exaggeration, but the independent Human Rights Commission of Pakistan has accused the government of “gross human rights violations” in Balochistan.