A powerful remote-controlled car bomb targeting a bus killed at least 11 people including nine Shiite pilgrims in Pakistan's insurgency-torn southwest on Thursday, police said.
The incident took place in the Hazar Ganji area on the outskirts of Quetta city, the capital of the oil and gas rich Baluchistan province bordering Iran and Afghanistan.
"A bus carrying Pakistani Shiite Muslims was coming to Quetta from Iran when a car bomb exploded near it, killing 11 people including nine Shiite pilgrims and two escorting policemen," senior local police official, Hamid Shakeel, told AFP.
"The victims included two female pilgrims.
"It was a remote controlled blast. The bomb was planted in a car and exploded as the bus passed by it," he said, adding that more than 20 people were injured in the attack.
He said the engine of the car was found about 50 feet away from the site of the explosion.
Two other senior police officials confirmed the explosion and casualties.
Manzoor Ahmed, a bomb disposal squad official, said the improvised explosive device weighed more than 30 kilograms.
The attack comes a day after a bomb planted under a tea stall at a railway station in southwestern Pakistan killed seven people, including a child, and wounded more than a dozen others.
Baluchistan has become an increasing flashpoint for sectarian violence between Pakistan's majority Sunni Muslims and minority Shiites, who account for around a fifth of the country's 167 million population.
Baluchistan is also rife with Islamist militancy and a regional insurgency waged by separatists who rose up in 2004 demanding political autonomy and a greater share of profits from the region's wealth of natural resources.
This month, UN human rights chief Navi Pillay voiced concern about "very grave" rights violations during Pakistani military operations.
It is one of the most deprived regions of Pakistan despite its wealth in resources, and human rights activists have accused the military of mass arrests and extra-judicial executions in its bid to put down the separatist insurgency.
Around 5,000 people have been killed in outbreaks of sectarian violence between Sunni and Shiite militant groups in Pakistan since the late 1980s.
Much of Pakistan, a key US ally in the war on Al-Qaeda and the 10-year fight against the Taliban in neighbouring Afghanistan, suffers from near daily Islamist militant violence.