The blast occurred in in the al-Rawda mosque in the town of Bir al-Abd, 25 miles from the North Sinai provincial capital of el-Arish, shortly after Friday prayers.
After the blast, gunmen in four off-road vehicles opened fire on the worshipers.
There was been no claim of responsibility as at the time of this article’s publishing.
Egypt has for years been battling an armed movement in the rugged and thinly populated Sinai Peninsula, which gained pace since the 2013 military ouster of the then president Mohamed Morsi of the Muslim Brotherhood.
In 2014, following a deadly suicide bombing that left 31 soldiers killed, Egyptian President Abdel Fattah el-Sisi declared a state of emergency in the peninsula describing it as a “nesting ground for terrorism and terrorists”.