According to news reports attributed to the Iraqi news agency Alsumaria and widely repeated elsewhere, chief clerics of the Islamic State (ISIS or ISIL) issued a fatwa (religious decree) on 4 October 2016 forbidding the breeding of cats inside homes in the ISIS-occupied city of Mosul.
Very few details of the fatwa were provided — indeed, it has yet to be independently verified that it was issued. The Arab news service Al-Masdar News provided these direct quotes from the original Alsumaria report:
Al Sumaria News, an Iraqi TV station, stated, “The Islamic State’s Central Fatwa Committee issued a fatwa (Islamic legal decree) prohibiting the breeding of cats inside houses in Mosul.”
“ISIS called on the residents of Mosul to obey the fatwa and not violate it,” Al Sumaria explained. “ISIS issued dozens of fatwas in Mosul based on its vision, ideology and beliefs,” Al Sumaria added.
Despite the circulation of variants of the report alleging that all ownership of cats and kittens is forbidden, and ISIS soldiers are going door-to-door in Mosul to enforce the prohibition, it's unclear whether these details came from the original source.
Based on the information provided on Islamic educational web sites, there does not appear to be any general prohibition on the ownership or breeding of cats in Islam. Indeed, as was pointed out in some of the news reportage on the fatwa, ISIS itself has been known to use photos of its soldiers posing with cuddly kittens in its online efforts to recruit young people to its cause.
"It is not known nor specified why ISIS issued the decree," according to Al-Masdar News.