Egypt announced it was doubling to one kilometre the depth of a security buffer zone it was creating on the border with the Gaza Strip after some of the worst anti-military violence since former president Mohamed Morsi was overthrown.

Egypt declared a state of emergency in the border area after at least 33 security personnel were killed last month in two attacks in the Sinai Peninsula, a remote but strategic region bordering Israel, Gaza and the Suez Canal.

It also accelerated plans to create a 500-metre deep buffer strip along the border by clearing houses and trees and destroying subterranean tunnels it says are used to smuggle arms from Gaza to militants in Sinai.

"A decision was taken to increase the buffer zone along the border in Rafah to one kilometre. The decision ... came after the discovery of underground tunnels with a total length of 800 to 1,000 metres," the MENA state news agency said on Tuesday.

Residents of Sinai, who complain they have long been neglected by the state, say they rely on smuggling goods through the tunnels for a living and that the creation of the buffer zone has stoked resentment.

Egyptian authorities see the tunnels as a threat and regularly destroy them.

Violence by armed groups in Sinai has surged since the army ousted the Muslim Brotherhood’s Morsi in July 2013. Since then, authorities launched a crackdown on the Brotherhood, jailing thousands of its members and labelling the party a terrorist organisation.

Ansar Bayt al-Maqdis, an armed group that has sworn allegiance to Islamic State of Iraq and the Levant group, has stepped up attacks on police and soldiers in Sinai and released a video this month in which it purported to claim that it was behind the October 24 attack.

Source: Reuters