Two suicide bomber were trying to enter the imambargah where people had gathered for Eid prayers, police said.
One of the suicide bombers was arrested in an injured condition.
The injured were shifted to the hospital.
Additional contingents of police have been deployed at the blast site.
IG Sindh AD Khwaja said the injured policemen were in critical condition and have been shifted to Sukkur. “If the need arise we will bring them to Karachi for treatment.”
Later during the day he visited the blast site. “Due to the timely action of the brave policemen we have been saved from a bigger tragedy,” he said.
He refused to share any other details about the attacker as the matter is still under investigation.
Meanwhile, mobile phone footage available show citizens asking questions to the injured attacker. He claims to have come from Balochistan, “I stayed at hotel before the attack,” he said.