Israel, Egypt, and Hamas agree on at least one thing: their mission to prevent the Islamic State terrorist group from expanding its grasp.

They chose to form an unlikely alliance against a ruthless ISIS affiliate that wreaked havoc on Egypt’s Sinai Peninsula – and claimed responsibility for downing a Russian plane in the region last year, The Washington Post reported Saturday.

Hamas two weeks ago sent several hundred fighters to Gaza’s border as part of a deal with Egypt to keep the extremists from entering the coastal territory.

Israeli Prime Minister Benjamin Netanyahu also praised his country’s decision to erect a new barrier between Israel and Egypt, warning that “we would have been overflowed by thousands of ISIS fighters from Sinai,” The Washington Post reports.

The ISIS affiliate known as Wilayat Sinai frequently has attacked Egyptian soldiers and military posts.

Egypt said it had the Sinai Peninsula under its control, claiming in statements that it captured or killed several terrorists. But the statements have been difficult to verify since journalists are barred from the region.

Egypt’s western allies are growing increasingly concerned about its ability to contain the ISIS outbreak, fearing it could threaten a multinational peacekeeping effort between Egypt and Israel along the Sinai border, The Washington Post adds.

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