A suicide bombing at a Shia procession in the southwestern Pakistani city of Quetta killed at least 43 people on Friday.

Injured people lie down in the road after an explosion during a Shia procession in Quetta, Pakistan, on Friday. (Arshad Butt/Associated Press)Police said 78 people were injured in the blast, some of them critically.

A member of the Pakistani Taliban later claimed responsibility for the attack.

Pakistani Taliban commander Qari Hussain Mehsud said that although his group was fighting the United States and the Pakistani government, "Shiites are also our target."

The procession urging solidarity among Pakistanis came as the country struggles to cope with extensive flooding.

After the blast, Shia youth fired shots into the air, and Allama Abbas Kumaili, a Shia leader, appealed for calm.

"We understand these are attempts to bring Sunni and Shiite sects against each other," Kumaili said.

The death toll this week from sectarian violence was already high. Earlier Friday, at least one person died in a bombing at a minority Ahmadi sect mosque. On Wednesday, in the eastern city of Lahore, 35 people died in a triple-suicide bombing at a Shia ceremony.

The flooding has left about 1,600 people dead and affected an estimated 20 million people.

With files from The Associated Press