Cairo, Jan 30 (IANS): The toll in Thursday's mortar attacks that targeted security premises in Egypt's North Sinai province rose to 33, a security source told Xinhua news agency Friday.

"The injured people include 31 military men and two civilians and they are being transferred from Arish to Cairo by air-ambulances for better treatment," the source added.

On Thursday evening, massive attacks with car bombs and mortar shells targeted security premises in Arish and left dozens dead and injured. The attacks extended to two big security checkpoints in nearby Rafah city.

Egypt has recently extended a curfew in many parts of North Sinai for three more months due to the unstable security conditions in the area and the recurrent terrorist attacks targeting security men and premises.

The anti-security attacks mounted in Sinai and other parts across the country since the ouster of Islamist president Mohamed Morsi by the military in July 2013 and the subsequent crackdown on his supporters left about 1,000 people dead while thousands more were arrested.

The attacks targeting security forces have killed hundreds.

Most of the attacks were claimed by Sinai-based Al Qaeda-inspired Ansar Bayt al-Maqdis group, which has recently changed its name to "Sinai State" after declaring its allegiance to the Islamic State terrorist group in Iraq and Syria.