Officials say a suicide bomber rammed into ta police bus, killing five policemen and two civilians and injuring 23 people near the legislative assembly of southwestern Balochistan province, of which Quetta is the capital.
A bomb went off in the centre of the Pakistani city of Quetta, capital of the province of Balochistan, killing seven people and wounding 23 on Tuesday, police and hospital officials said.
The blast targeted a police truck close to a high security area where the provincial assembly and other government offices are located. A suicide bomber was believed to have walked up to the truck and blown himself up, senior police officer Abdul Razzaq Cheema told Reuters.
The bodies of five policemen and two civilians, as well as the wounded victims, were brought to the Civil Hospital, Dr Waseem Baig said, adding that death toll could climb as some of the injured were in serious condition.
"At least five policemen and a pedestrian were martyred and 16 others were wounded when a suicide bomber on a motorcycle struck the bus," senior police official Abdul Razzaq Cheema said earlier.
There were no immediate claims of responsibility for the attack, he added.
The attack took place hours after the chief minister of the province, Nawab Sanaullah Zehri resigned to end "instability" in the gas-rich province, his spokesman said, amid opposition efforts to remove him through a vote of no confidence.
Zehri quit shortly before a provincial assembly session in which lawmakers were expected to table a motion to demand a vote to oust him.
"I can confirm CM Baluchistan tendered resignation following the spirit of democratic principles," Jan Achakzai, Zehri's spokesman, said on Twitter.
I can confirm CM Balochistan tendered resignation following spirit of democratic principles. He thanked party MPAs & coalition partners 4 their support. He decided 2 bring an end to instability. He said #CPEC 2 continue.— Jan Achakzai (@Jan_Achakzai) January 9, 2018
Mir Abdul Qudoos Bizenjo, a former deputy speaker of the provincial assembly and one of the main instigators behind Zehri's removal, said lawmakers sought to oust Zehri because of his "massive corruption" and "ignoring coalition partners."
Zehri, a member of the governing Pakistan Muslim League-Nawaz (PML-N), rejected accusations of corruption.
Police and troops have been battling militants and separatist groups in mineral-rich Balochistan for more than a decade.
Balochistan, bordering Iran and Afghanistan, is the largest of the country's four provinces but its roughly seven million people have long argued they do not get a fair share of its vast gas and mineral wealth that have largely remained untapped.
The province also forms an important leg of the $57 billion China-Pakistan Economic Corridor of energy and infrastructure projects that China hopes to build as part of its belt and road initiative.
The province is Pakistan's most restive region, afflicted by militancy, sectarian violence, and the separatist insurgency.
Last month two suicide bombers stormed a packed Christian church in the region killing nine people and wounding up to 56, in the latest attack claimed by Daesh in the country.