Doha
12 May 2017
(AlJazeera)

At least 37 people who received serious wounds from the blast were transferred to Quetta, said Dr Ahmed. They mainly suffered from shrapnel wounds, he said.

Television footage from the scene showed several badly damaged vehicles and motorcycles, with windscreens shattered and severe blast damage visible, as the police established a cordon around the site.

Haideri himself spoke to local media over the phone while en route to the hospital, saying he was not badly wounded.

"I am fine, thank God. I have been wounded. I am being taken to the [Combined Military Hospital in Quetta]," Haideri told Pakistan's Geo News television channel.

"The explosion happened on my car ... the glass from the front windscreen hit me, and the side door also buckled after the blast," he added.

Anwar ul-Haq Kakar, spokesman for the Balochistan provincial government, told Al Jazeera that the attack occurred when Haideri was leaving a mosque after Friday prayers.

"As soon as they started the journey back there was an explosion," Kakar said.

"Law enforcement personnel are collecting evidence at the site and examining the crime scene. It would be premature to say what kind of blast it was at this stage."

Haideri is a member of the right-wing religious Jamaat Ulema Islam party's Fazl faction (JUI-F), and has been a senator since 2008. He has been the deputy chairman of the Senate since 2015.

He has previously represented his native district of Kalat, also in Balochistan, in the lower house of parliament.

In February, Pakistan's Senate boycotted a UN-sponsored event in the United States in protest against an "undue delay" by the US in issuing a visa to Haideri to attend.

Asad Hashim is Al Jazeera's Web Correspondent in Pakistan. He tweets @AsadHashim.