Hamas’ senior commander Saber Siam was killed on Sunday after ISIS loyalists placed a bomb in his vehicle.
ISIS militants said in a statement that Siam was killed because he was “a partner in a declared war against religion and against Muslims, working for the heretical government in Gaza,” according to Israeli reports.
The attack was conducted by ISIS-affiliated Salafist rebels who have also warned local residents to stay away from Hamas offices and buildings as it plans to carry out more attacks.
The conflict between Hamas and ISIS in Gaza started when Palestinian forces demolished a makeshift mosque used by Ansar al-Bayt al-Maqdis in early May.
Ansar al-Bayt al-Maqdis is an Egyptian Islamist group that has pledged allegiance to ISIS and has been recruiting Palestinians for the Islamic State.
After demolishing the Almtahabin mosque, Hamas then arrested seven men, including a local Salafist Sheikh Yasser Abu Houli.
ISIS claims it will kill Hamas personnel “one by one” and that it knows the names and addresses of all the officers working for the Palestinian Intelligence agency.