Netanyahu waxed broadly of a Middle East in turmoil on Sunday, in his first public comments on the threat posed to the region by ISIS, a terrorist militia conquering swaths of territory in eastern Syria and northern Iraq.

Threatening a borderless conflict between “extremist Shi’ites,” funded by leadership of the Islamic Republic of Iran, and equally extreme Sunnis— a soft “alliance” between ISIS and al Qaeda— the Israeli prime minister suggested the United States should largely stay out of the fight, and instead allow the parties to weaken one another.

Western diplomats working to end the nuclear crisis holding up such plans should fashion a deal with Iran similar to an agreement reached last fall, brokered by Russia and the US, that rid Syria’s President Bashar Assad of his massive chemical weapons stockpile, Netanyahu said, calling the Syrian accord a “good deal.”

World powers are currently negotiating with Iran in Vienna towards a comprehensive solution to the crisis. The US, Israel and its allies suspect Iran’s nuclear program has military dimensions.

In August, Foreign Policy reported that Islamic State was also trying to develop biological weapons. The report cited information found on a laptop computer seized from an IS operative.

Foreign Policy obtained the computer from a moderate Syrian rebel group who seized the laptop in the Idlib province from an Islamic State hideout whose fighters had fled.

The laptop, belonging to a Tunisian operative of the Islamic State, named Muhammed S., with a background in chemistry and physics, included a 19-page document on developing biological weapons and weaponizing the bubonic plague.

“The advantage of biological weapons is that they do not cost a lot of money, while the human casualties can be huge,” the document says in Arabic, according to Foreign Policy.

Among the files on the seized computer is also a ruling from a Saudi cleric justifying the use of weapons of mass destruction. “If Muslims cannot defeat the unbelievers in a different way, it is permissible to use weapons of mass destruction…Even if it kills all of them and wipes them and their descendants off the face of the Earth.”

The British newspaper The Sunday Times reported on Sunday morning that Islamic State is calling on its members to brace for war with Iran in order to take over its nuclear secrets. The newspaper cited a document believed to have been written by top Islamic State member Abdullah Ahmed al-Meshedani, a member of the group’s highly secretive six-man war cabinet.