Egyptian security forces carry the casket of a policeman killed in north Sinai by Islamist militants in 2013.Mohamed Abd El Ghany / Reuters

A series of coordinated attacks by a terror group affiliated with the Islamic State killed over 50 Egyptian soldiers in Sinai on Wednesday, unleashing what’s being described as “the fiercest clashes in decades in the peninsula.”

The attacks took place in the Sheikh Zuweid area of north Sinai province, where a number of military checkpoints and installations were targeted. The assaults coincided with a battle for information, with the Egyptian security forces initially reported that only 10 soldiers had died in the attacks despite higher estimates by the media and medical workers. Meanwhile, “Sinai Province,” the ISIS affiliate, claimed it had attacked 15 checkpoints, while others put the number closer to five. Northern Sinai has been under a government-imposed media blackout since 2013.  

What is known is that this is one of the biggest and most brazen jihadist attacks in recent memory. Among the most significant developments is the ISIS claim that it has taken over Egyptian territory. “We have total control of many sites, and have seized what was in them,” read a statement by the group. A number of Egyptian soldiers were reportedly taken captive.

If ISIS does indeed control this territory, it would mark a new milestone for the group in Egypt. “Isis has previously launched several bloody attacks on the Egyptian army in the north-eastern part of the peninsula—most notably this January and last October,” wrote The Guardian’s Patrick Kingsley. “But after those assaults, Isis quickly retreated—whereas after Wednesday’s attack the group appeared to try to advance.”

“What we’re seeing is that Sinai Province has developed a real tactical proficiency,”said Eric Trager of the Washington Institute. “The Egyptian military campaign in Sinai has not sufficiently weakened the organization.”

What may be enabling an ISIS affiliate to take root in Sinai, which is just miles from the Gaza Strip, is what one analyst characterized as the Egyptian army’s “scorched earth” military campaign against the terror groups in Sinai. Trager told me that the military’s “heavy-handed” efforts have alienated the local population.

“Many Sinai residents are neither with the army or with Sinai Province, and that in and of itself reflects a failure,” he added. “Winning over the local population is a cornerstone of any counterinsurgency.”

Wednesday’s violence follows the killing of Hisham Barakat, Egypt’s top prosecutor. Barakat, who was killed in a daylight car bomb in Cairo on Monday, is the highest-ranking Egyptian official to die in the unrest that followed the ouster of Mohammed Morsi, a Muslim Brotherhood leader and Egypt’s former president. As clashes continued in Sinai, Egyptian security forces conducted raids against Muslim Brotherhood members in Cairo, killing several people and raising fears that the country’s instability is deepening.

On Wednesday afternoon, the White House condemned the attack against Egypt, adding that the United States “stands resolutely” behind the Egyptian government.

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