RNA - According to AFP, the blast hit the mosque in Shikarpur in Sindh province, around 470 kilometers (300 miles) north of Karachi, as hundreds of worshippers attended Friday prayers.
Sindh health minister Jam Mehtab Daher told AFP that "a total of 40 have been killed in the attack, 46 others have been wounded".
Shaukat Ali Memon, the medical superintendent of Civil Hospital in Shikarpur, confirmed the death toll and warned it could rise further as many of the wounded were in a critical condition.
Hundreds of people rushed to the scene after the blast to try to dig out survivors trapped under the roof of the mosque, which collapsed in the explosion, witness Zahid Noon said.
Television footage of the aftermath showed chaotic rescue scenes as people piled the wounded into cars, motorbikes and rickshaws to take them for treatment.
Abdul Quddus, a senior police official in Shikarpur, told AFP the initial investigation suggested it may have been a suicide attack.
Friday's attack came as Prime Minister Nawaz Sharif visited Karachi, the capital of Sindh province, to discuss the law and order situation in the city.
R111/108/C/