An Egyptian Christian school teacher has been gunned down on the way to work by suspected ISIS militants in Sinai, Egypt.

It was the second killing of a Christian in under a week in the area.

Gamal Tawfiq, 50, was shot in the head on the way to El-Samran School in el-Arish, Northern Sinai. His two killers rode by motorbike and had followed Tawfiq from his home, Associated Press reports.

There has been no official claim of responsibility, but a security official said that ISIS militants in Sinai were the main suspects.

Less than a week before on Sunday, militants shot and killed a local vet Bahgat Zakher, in el-Arish. In January Wael Milad, a merchant was gunned down by militants in his shop. Both men, like Tawfiq, were Coptic Christians.

In a brutal killing spree in January, five Coptic Christians in Egypt were murdered, all found with their throats slashed.

ISIS claimed responsibility for a suicide bombing of a Cairo church in December that killed 27 people and wounded over 40. The terrorist group called the attack a 'martyrdom operation' targeted at 'infidels' and 'apostates'.

Egypt has an estimated population of nine million Christians. Mostly Orthodox Copts, they account for about 10 per cent of Egypt's population, which is overwhelmingly Sunni Muslim.

'For long, incidents of shooting and killing Christians were sporadic, but recently we are witnessing an increase that I think will turn into a repetitive pattern in el-Arish,' said Ishaq Ibrahim, a researcher at the Egyptian Initiative for Personal Rights.