Soon after the explosion on Monday evening, police and rescue staff reached the spot and started shifting bodies and injured people to local hospital for medico-legal formalities, Pakistan's Dunya news reported.
The nature of the blast was not immediately clear. Security officials have also cordoned off the site of the blast.
Fida Mohammad, who was attending evening prayers, said about 60 people were present at the time of the attack on the mosque, which is located in a densely populated area.
The explosion ripped through the front row of worshippers seconds after the prayer began, he said. "It was a powerful blast, people were screaming and running here and there -- many people were injured because of the stampede," Mohammad said.
Talking to media, Provincial home minister Zia Ullah Langu said that investigations by bomb disposal officers indicated that a suicide bomber carried out the attack.
Quetta is the capital of Balochistan province, the country's largest but most sparsely populated province, rich in mineral resources and the route of much of the $60bn China-Pakistan Economic Corridor (CPEC) project.(UNI)
