Israel fears that a jihadist offensive that has conquered large areas of Iraq may prompt American concessions to arch-foe Iran, reports Israel National News.

“If Washington needs Tehran’s help to solve the Iraq crisis, the United States will need to be more flexible in negotiations on Iran’s nuclear program,” Voice of Israel public radio cited a senior official as saying.

Tourism Minister Uzi Landau warned: “We’re in a situation where, to confront the threat from the global jihad, we rely on Iran and its allies.”

The rise of the jihadist Islamic State in Iraq and the Levant, known as ISIL or ISIS, which has seized Iraq’s second city Mosul and a swathe of its north and center over the past 10 days, has prompted talk of possible cooperation between Washington and Tehran to help stop the insurgency.

A top Iranian official said on Wednesday that Tehran could consider working with the United States over the crisis in Iraq if talks on its nuclear program are successful.

The Iranian official’s comments came after US Secretary of State John Kerry said Monday he would be open to cooperating with Iran on Iraq.

“I wouldn’t rule out anything that would be constructive,” Kerry told Yahoo News when asked if the United States would cooperate militarily with Iran, one of Iraqi Prime Minister Nuri al-Maliki’s key allies.

US Deputy Secretary of State William Burns held a brief meeting with Iranian officials in Vienna on Monday on the sidelines of talks between Tehran and the major powers over its controversial nuclear program.

Israel is wary of any agreement that leaves Iran with nuclear capability.  Recent high-level U.S.-Iran talks that were meant to pave the way to a final nuclear deal only highlighted the two nations’ huge differences, said diplomats. Israel fears that America may make dangerous concessions in order to secure Iranian cooperation on operations in Iraq.

For example, on the subject of uranium enrichment, Iran wants to keep the almost 20,000 enriching centrifuges it now operates or has on standby. And it wants to ultimately expand the number to 150,000 — or replace them with advanced models that have that same output.

The U.S. demands that Iran run no more than a few hundred centrifuges, dismantle all on standby and agree to tight limits on how much enriched uranium it can stockpile.

Similarly, a nearly built reactor at Arak, southwest of Tehran, would produce substantial amounts of waste plutonium. Like enriched uranium, that’s a potential pathway to nuclear arms. Iran is resisting demands that it completely re-engineer the plant and is ready only to reduce the amount of plutonium produced. The U.S., fearing that any reduction may be reversible, is only ready to accept a model that cannot be reverse-engineered.