A bomb went off in the center 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 told Reuters, adding that death toll could climb as some of the injured were in serious condition.

The attack took place hours after the provincial chief minister, Sanaullah Zehri, resigned, although there was no indication that the blast was connected to provincial politics.

Zehri quit after some members of his PML-N party rebelled against him to back a no-confidence motion in the provincial assembly, where he no longer commanded majority support.

Balochistan is an important leg in 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.

Last month two suicide bombers stormed a packed Christian church in southwestern Pakistan killing nine people and wounding up to 56, in the latest attack claimed by Islamic State in the country.