CAIRO

An Egyptian police officer was killed Wednesday when his vehicle struck a roadside bomb in the northern Sinai Peninsula, according to an Egyptian security source.

Egyptian state media quoted an unnamed security source as saying that the incident had occurred in northern Sinai's Bir al-Abd region.  

The same source said the blast had been caused by a 50-kilogram bomb planted by "unknown persons".  

No group has yet claimed responsibility for the bombing.

Egypt's Sinai Peninsula has remained the epicenter of a militant insurgency since mid-2013, when the army ousted Mohamed Morsi -- Egypt's first freely elected president -- in a bloody military coup.