An explosion at a Shiite protest in Quetta, Pakistan, killed more than 40 people Friday.
Protesters were expressing their support for Palestine and speaking out against Israel. The attack is the second in only three days.
On Wednesday, three suicide bombers targeted a Shiite procession in Lahore, killing more than 30 people. The Taliban has claimed responsibility for the attacks, but officials said it is still unclear who is behind it.
"We proudly take its responsibility. Our war is against America and Pakistan security forces, but Shiites are also our target because they too are our enemies," Pakistani Taliban commander Qari Hussain Mehsud said.
Unite Nations Secretary General Ban Ki-moon strongly condemned the attacks. A U.N. spokesman said, "These attacks, which deliberately targeted Shiite Muslims and killed or injured scores of civilians, are unacceptable."
Militants are increasing their attacks to pressure the Pakistani government which is already struggling to deal with a flooding crisis that has killed more than 1,600 people.