PARACHINAR, Pakistan - Ten people were killed and at least 50 injured in a blast in the northwestern Pakistani city of Parachinar on Sunday, officials said, but it was unclear which militant group was responsible.Parachinar has a large Shi'ite population, unusual in Sunni-majority Pakistan, and locals have expressed fears that militias who splintered from the Taliban and sworn allegiance to Islamic State might target them.Pakistan also has its own sectarian militant groups, most notably Lashkar-e-Jhangvi (LeJ). Most of LeJ's leadership were shot dead in police custody this year; police say they were trying to escape.No group has yet claimed responsibility for Sunday's blast.Parachinar local government official Riaz Hussain said the blast targeted crowds at a market."A blast in Eid Gah market in Parachinar killed 10 people including a child and wounded at least 50 others," said Amjad Ali Khan, the political head of Kurram Agency. Parachinar is the capital of Kurram. "Some of the injured are in critical condition and we are planning to send them to Peshawar and Kohat for better treatment," said Shafiq Hussain, a health worker at the Agency Headquarters Hospital Parachinar.Some of the people suffered injuries due to a stampede after the explosion, he said.