Egypt has permitted Israel to conduct over a hundred aerial raids on the Islamic State group affiliate in Sinai, the restive desert peninsula that shares a border with Israel, the New York Times claimed Saturday.

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The report details what it calls a "covert war" in Sinai in which "unmarked Israeli drones, helicopters and jets" have been allowed to carry out over 100 raids inside Egyptian territory for over two years, at times more than once a week.

According to the report, American officials credit the wave of Israeli airstrikes — which the Times said began at around the time that the Sinai Province branch of Islamic State brought down a Russian charter plane over the peninsula, resulting in the deaths of the 224 people it carried — "with killing a long roster of militant leaders" in Sinai.

The Times cited as sources for its report "[s]even current or former British and American officials involved in Middle East policy," all of whom spoke on condition of anonymity.

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Sinai is largely demilitarized as part of the Israeli-Egyptian peace treaty of 1979 but Egypt approved Israeli operations as part of the war on ISIS in Sinai. Israel has also been permitted to act to combat arms smuggling by Palestinians into Gaza.

According to The New York Times, Israel's aid in attacking the militants in Sinai is what allowed it to gain the upper hand in an ongoing war.

But to avoid public relations damage in Egypt were news of the Israeli contribution to get out, the Times says, Israel must cover it tracks: All identifying markings on its drones and aircraft are covered, and some Israeli planes and helicopters fly looping routes in order to create the semblance of being local. So concerned is the Egyptian regime that it has even closed Sinai off to journalists, the report claimed, just to make sure news of the cooperation with Israel does not get out.