A large-scale Hamas attack threatens to significantly escalate conflict between Israel and militant groups. Violence could spread from Gaza to the West Bank, and attacks from Lebanon and unrest within Israel proper are also possible. Hamas, the Palestinian militant group that governs the Gaza Strip, and other armed groups like Palestinian Islamic Jihad (PIJ) launched a surprise attack Oct. 7 against Israel, firing thousands of rockets and carrying out a rare mass ground incursion into southern Israel. At least 100 Israeli casualties were reported, including soldiers and civilians, with many of them apparently caused by the ground incursion that targeted settlements, cities and at least one Israel Defense Forces base. Though details continue to emerge, Israeli media reported at least one IDF base had lost communications during the attack, while Hamas had reportedly made off with IDF equipment and a number of Israeli hostages.