The move comes five days after militants carried out one of the deadliest attacks in decades against Egypt’s security forces and is intended to increase the military's stranglehold over restive Sinai Peninsula.
It could also be read as a face saving measure for Egypt’s wildly popular army, by shifting blame for its own security failures onto outside powers, namely Hamas, the militant organization that runs Gaza.
Last Friday, militants killed 33 soldiers in two attacks at the Rafah border area, prompting Egypt to declare a state of emergency across North Sinai and to close the Gaza border crossing indefinitely. In an angry speech the following day, President Abdel Fattah Al-Sisi, a former military commander, said Egyptians were locked in an “existential war” with jihadi militants.
No group has claimed responsibility for the attack. In the past year, a fragmented insurgency has gathered pace after the overthrow of an Islamist president; hundreds of security personnel have been killed, and several Sinai residents have been beheaded as suspected Israeli spies by Ansar Bayt el Maqdis, a militant group in Sinai that is seen as the most likely hand behind the latest incident.
Egyptian security officials say they must evacuate 800 houses to make way for a buffer zone along the eastern border. The planned zone is 500 meters wide, or just under one third of a mile, and is slated to include water-filled trenches that would thwart the extension of a vast network of smuggling tunnels linking Gaza to Egypt.
Anonymous Egyptian security officials have told local media they believe Friday's attack was abetted by weapons from Gaza, a familiar line of reasoning here. Egypt has long accused Hamas of meddling in Egyptian affairs. Hamas officials deny any interference and criticize Egypt for stricter border crossing rules since the overthrow of Mohamed Morsi, the former Islamist president.
Ansar Bayt el Maqdis is known to have cultivated ties with militants in Gaza. Still, there is no evidence to suggest Palestinian fighters played a role in the attack. The group is believed to source its weapons through a range of regional networks, stretching from Libya to Sudan.
Dust and confusion
On Wednesday, Egypt's army forged ahead with its campaign to seal off Sinai from Gaza. As work on the buffer zone began, photos circulating on social media showed rudimentary apartment blocks exploding into clouds of dust.
Speaking on the phone from Rafah, a local resident calling herself Um Mohamed said she'd seen hundreds of residents leaving the area in a state of confusion. "The people don't know what to do," she said. "Some took their stuff in cars, others set up camp in the street."
North Sinai has long been socially and economically marginalized by Egypt's central government, and has been under de-facto military occupation since the army escalated a campaign against Ansar Bayt el Maqdis in the summer of last year.
The military controls traffic in and out of the area and conducts frequent raids on alleged weapons stores and militant hideouts in a patchwork of villages running eastwards from the city of El Arish. It says it has destroyed the majority of the smuggling tunnels between Gaza and Egypt over the past year. For some, this raises the question of why such punitive action is now needed in the borderlands.
"The military's position is that [Friday's attack] cannot be due to failures on its end," says Zack Gold, an adjunct fellow at the Washington-based American Security Project. In 2012, Mr. Morsi forced out military chiefs after another mass killing of soldiers exposed shortcomings. "The drastic move of creating a buffer zone is preferable to the drastic move of firing the military leadership," says Mr. Gold.