Israeli and Egyptian forces are secret allies in a battle with ISIS, according to a startling new report.

The New York Times said Saturday that unmarked Israeli drones, helicopters and planes conducted more than 100 strikes against the jihadis in Egypt’s northern Sinai over a period of more than two years.

The clandestine missions, the report says, have the blessing of Egyptian President Abdel Fattah el-Sisi, who realized he desperately needed help.

American officials, the newspaper said, believe the collaboration helped the Egyptian military gain the upper hand in its nearly five-year battle with the militants.

The need for secrecy is so great that the only Egyptians who know about the de facto alliance are a small number of military and intelligence officers.

Some of the aircraft fly circuitous routes to their targets so they don’t appear to come from Israel, the Times said.