An Islamic State (IS) offshoot launched Friday a mortar attack on an Ezzeddine Al Kassam Brigades' military site in the southern Gaza Strip city of Khan Yunis, state-run Middle East News Agency (MENA) reported. Two mortar shells targeted Al Kadiseya site owned by Al Kassam (military wing of the Hamas Movement), Palestinian news websites cited a statement issued Friday by the IS-related Islamic State Supporters in Jerusalem (ISSJ) terrorist group. "To the last breath, we will never give up freeing our brothers jailed in Gaza despite meager capabilities and lack of supporters," the statement read. The statement called upon Al Kassam affiliates to join ranks and other Muslim grassroots to steer away from police checkpoints to save their lives. The IS-offshoot threatened the Hamas Movement on May 3 of "dire consequences at the horizon" in case the Salafist prisoners were not released. Spokesperson for Hamas refuted the threats, stressing that the security situation in the Islamist-run strip was stable. Hamas-linked police forces reportedly destroyed an (ISSJ) mosque in Deir Al Balah city and arrested a large number of Salafists, a move the latter likened to Israeli brutalities. Media reports said earlier this week that IS called its affiliates in Egypt's Sinai Peninsula to flock to the neighboring strip for an imminent battle against Hamas.