At least 15 people have been killed and over two dozen severely injured in a bomb attack on a Shia mosque and religious seminary in Pakistan's northwestern city of Peshawar Local security officials said the attack occurred when people were performing Friday prayers on the outskirts of the volatile city. Medical sources said the death toll is expected to rise as some of the injured are reported to be in critical condition. No group has yet claimed responsibility, but pro-Taliban militants usually take responsibility for similar attacks in the violence-wracked country. The blast is the worst such attack in the volatile region since the new government was installed in May. This is also the latest deadly incident in a wave of violence against the Shia Muslim community in Pakistan. Human Rights Watch says more than 400 Shias were killed in Pakistan in 2012, which was the deadliest year on record for the Shia Muslim community. Reports say the anti-Shia terrorist group of Lashkar-e-Jhangvi (LeJ) was behind most of the attacks on Shia Muslims in Pakistan. Shia Muslims in Pakistan say the government must take decisive action against the forces involved in the targeted killings. They also accuse Islamabad of failing to provide security for the Muslim community. The country’s Shia leaders have called on the government to form a judicial commission to investigate the bloodshed. The killing of Shias has caused an international outrage, with rights groups and regional countries expressing concern over the ongoing deadly violence. Shias make up about a third of Pakistan’s population of over 180 million.