The Islamic State's affiliate in Egypt's Sinai Peninsula (Wilayat Sinai) released a video on Wednesday (3 January 2018) declaring war on Hamas, the Islamist militant group that controls the neighbouring Gaza Strip. The video included the execution of an alleged former Islamic State member accused by the group of having smuggled weapons to Hamas's military wing, the Izz al-Din al-Qassem Brigades, and cited as justification Hamas's failure to effectively respond to the US recognition of Jerusalem as the capital of Israel, and an ongoing crackdown by Hamas on Islamic State and Salafist fighters in Gaza. Hamas, in collaboration with Egypt, has been securing the Sinai border since June 2017 – restricting access to weapons and recruits for Wilayat Sinai's insurgency against the Egyptian state (see Egypt - Israel - Palestinian Authority: 18 August 2017: Suicide attack on Hamas militants indicates evolving security relationship with Egypt and continuation of Palestinian reconciliation).
Significance: Wilayat Sinai, or any Islamic State affiliates in Gaza such as the Sheikh Omar Hadid Brigade, are extremely unlikely to have the capability to successfully challenge Hamas's control of Gaza. Since early December 2017, members of Salafist groups have reportedly been arrested in an attempt to prevent 'unauthorised' rocket and mortar attacks against Israel that risk provoking a major response and initiate a wider military conflict. Izz al-Din al-Qassem Brigades members far outnumber members of rival militant groups. It is likely that Wilayat Sinai will attempt to prove its religious jihadist credentials and exploit the ongoing debate around Jerusalem by launching rockets or mortars from northern Sinai towards Israel. The most likely target is the city of Eilat, but any such rocket fire is unlikely to consist of more than five Grad-type rockets, which are likely to be intercepted by Israel's missile defense system. Islamic State affiliates in Gaza are more likely to target Israeli residential settlements. Casualties from these attacks, rather than material property damage, would be highly likely to lead to greater Israeli willingness to commit to an escalation in conflict. The highest risk to civilian buildings and residential areas is to Ashkelon and Sderot, and all settlements neighbouring the Gaza border, such as Alumim and Kibbutz Kissufim. Within Gaza, Islamic State militants are likely to attempt assassinations of senior Hamas figures or attack checkpoints and administrative buildings with small arms or suicide bombings.