Pakistani authorities have identified the attacker who targeted a mosque in the capital Islamabad as a resident of Peshawar who received training in Afghanistan, raising renewed concerns about cross-border militancy, Germany’s DPA news agency reported.

According to preliminary information cited by Pakistan’s Geo News television network, the attacker, identified as Yasser Khan Yasser, had been living in Afghanistan for about five months before returning to Pakistan.

Investigators are also examining possible links between the attacker and Islamic State’s Khorasan Province, an affiliate of the militant group active in parts of Central and South Asia. Officials said the investigation is still at an early stage.

Pakistani authorities did not immediately provide further details on the motive behind the attack or when the investigation would be concluded.