Egyptian troops killed 12 suspected militants in fresh assaults in the restive Sinai Peninsula, where the military continues to combat an Islamist insurgency, an army spokesperson said.

Seventy others suspected of carrying out "terrorist" attacks against army and police forces were arrested in raids that took place from 3 to 10 December in the in the border region, which adjoins Israel and the Palestinian Gaza Strip, army spokesperson Mohamed Samir said Thursday in a statement.

Late in October, 31 soldiers were killed in two militant attacks in North Sinai, the deadliest violence since the 2013 ouster of Islamist president Mohamed Morsi unleashed a spike in militant activities.

The attacks were claimed by the Sinai-based Ansar Beit al-Maqdis, a militant group that has sworn allegiance to the Islamic State.

The army has struggled to crush militant violence based in Sinai which has killed hundreds of police and troops and at times expanded to mainland cities including Cairo.

Last month, the army began demolishing houses and clearing residents  in the border city of Rafah as part of its evacuation plan to set up a buffer zone aimed at deterring militant infiltration and arms smuggling.

The move came in the aftermath of the deadly October attacks.