Islamabad, Pakistan - A roadside bomb explosion in the southwestern Pakistani city of Quetta has killed at least two police personnel, including a senior police officer, authorities say, the latest in a series of attacks on police in the restive province of Balochistan.

Senior officer Hamid Shakil and his driver were killed, while at least three others were wounded, in the explosion on Thursday morning, which targeted Shakil's vehicle, Quetta police chief Abdul Razzaq Cheema told Al Jazeera.

Local police official Naimatullah confirmed the death toll, although he said it was not immediately clear whether the explosion was caused by a roadside IED or a suicide attacker.

"He was going from his home in Chaman Housing Scheme [area of the city] to his office when the blast occurred," said Naimatullah, who goes by only one name.

Shakil was serving as a Deputy Inspector General (DIG), the second highest rank in the provincial police force.

Images from the scene showed the mangled remains of his pick-up truck, the front and passenger side of the vehicle appearing to have borne the brunt of the blast.

Series of attacks

The explosion took place in the heart of the provincial capital of Balochistan, which has seen a series of attacks on police personnel and others in recent days.

On October 18, seven police officers were killed and 22 wounded when their vehicle was targeted in a roadside suicide bombing in the Saryab road area of Quetta.

Earlier in October, five people were killed in an attack aimed at the city's sizeable Hazara Shia Muslim community.

Days earlier, a suicide bomber killed at least 18 people at a shrine in the town of Jhal Magsi, about 165km south of Quetta.

Balochistan has been at the centre of attacks by both armed religious groups such as the Tehreek-e-Taliban Pakistan (also known as the Pakistani Taliban) and armed ethnic Baloch separatists fighting for independence from Pakistan.

Increasingly, it has come under fire from local affiliates of the Islamic State of Iraq and the Levant (ISIL) group, such as the Lashkar-e-Jhangvi's Al-Alami faction.

The province has also been at the centre of much of the transport infrastructure development related to the $56bn China Pakistan Economic Corridor (CPEC), a trade corridor linking southwestern China to the Arabian Sea through Pakistan that culminates in the Gwadar port in southern Balochistan.

Baloch separatist fighters have often claimed responsibility for attacks on security and police personnel deployed to protect construction projects along the corridor.

Follow Asad Hashim on Twitter: @AsadHashim