NEW DELHI: Global terror outfit Islamic State has claimed responsibility for the deadly blast at a Shia mosque in Islamabad that led to over three dozen casualties on Friday. Toll rose to 36 on Saturday after some critically injured people died in hospitals, said a PTI report. In a related development that has attracted the attention of Indian security establishment, the Islamic State in its latest al-Naba issue called on members of Lashkar-e-Taiba (LeT) to defect and join the Islamic State in Khorasan Province. The claim regarding the blast was issued via IS central’s mouthpiece, Amaq, stating the attack was a Fidayeen operation carried out by a soldier of the Islamic State in Pakistan Province (ISPP) — active since 2019 — inside the mosque compound. Amaq claimed over 200 casualties in contrast to the official Pak govt admission of 36 deaths and injuries to scores. The suicide bomber was identified by Amaq as Saifullah Ansari. His photograph taking the bayah (oath of allegiance) was also posted by the IS mouthpiece. The statement also mentioned that hundreds of Pakistani Shias had joined the pro-Iran ‘Zaynabiyoun brigade’ militia in Syria. The claim by Amaq followed an official denial by Tehreek-e-Taliban Pakistan (TTP), which strongly rebutted any involvement in the incident. The blast, which occurred during prayers at the Khadijatul Kubra mosque in Tarlai area, was the deadliest in Islamabad since the 2008 Marriott hotel bombing. The explosion coincided with the visit of Uzbek President Shavkat Mirziyoyev to Pakistan. The attack is being seen as a result of growing sectarian tensions in the country. Earlier in Jan, ISKP had claimed responsibility for a blast in Bajaur district that killed a senior Lashkar commander named Najibullah.