An Egyptian security chief says suspected Islamic militants have gunned down a Coptic Christian teacher on his way to school in northern Sinai.

It's the second incident involving a Christian slain by suspected militants in less than a week.

The security official says the 50-year-old Gamal Tawfiq was shot in the head by two militants on a motorbike who were following him on Thursday morning as he walked from his home to work at El-Somran School in the city of el-Arish.

He says authorities suspect the Islamic State's affiliate in Sinai in the killing.

The school principal confirmed Tawfiq's death to The Associated Press but declined to give details.

Both the security official and the principal spoke on condition of anonymity because they are not authorized to speak to reporters.