The death toll from a suicide bombing at a mosque in the south-western Pakistani city of Quetta rose to 15 on Saturday, officials said. The blast during Friday evening prayers wounded at least 20 other people, police said. "Two of the wounded people died overnight in the hospital," provincial home minister Zia Langove said. Six people were still in a critical condition. Fida Mohammad, who was attending evening prayers, said about 60 people were present at the time of the attack. The explosion ripped through the front row of worshippers seconds after the prayer began, he told AFP. "It was a powerful blast, people were screaming and running here and there – many people were injured because of the stampede," he said. ISIS claimed its suicide bomber carried out the attack to target an Afghan Taliban seminary. The Taliban denied in a statement that some of its members, including a senior commander, were killed. Local officials in Quetta's police and district administration would not confirm whether the Dar-ul-Aloom Shariah seminary belonged to the Afghan Taliban. Pakistan denies the presence of the group on its soil. However, two officials said on condition of anonymity that the seminary was part of the Afghan Taliban. Balochistan is Pakistan's largest and poorest province, bordering Afghanistan and Iran. It is rife with extremist, separatist and sectarian insurgencies and attacks are frequent, even as the number of violent incidents has significantly dropped elsewhere in Pakistan. The separatist and nationalist groups are demanding a greater share in revenues from the province's rich mineral and gas resources. Extremist militant groups including ISIS, which consists of splinters from local Taliban and sectarian groups, also have a strong presence in the region. The mosque bombing came two days after a motorcycle bomb targeting a paramilitary vehicle killed two people and wounded 14 others at a busy market in Quetta. Police said they had foiled another attack by killing a suicide attacker in Rawalpindi city near Islamabad after he shot and killed two policemen. Balochistan is at the centre of the $60 billion (Dh220bn) China-Pakistan Economic Corridor, part of China's Belt and Road project. But violence in the province has fuelled concerns about the security of projects such as a planned energy link from western China to Pakistan's southern port of Gwadar.