Last month, America’s top Iran negotiator Wendy Sherman had some bad news for ambassadors from America’s Arab allies. In a meeting with envoys from Saudi Arabia, the United Arab Emirates, and other Gulf states, Sherman said that any bargain with Iran would likely leave Tehran, the Gulf states long-time enemy, with the capacity to enrich uranium, according to U.S. officials briefed on the encounter.

Sherman regularly briefs these allies after diplomatic talks with Iran, but in recent weeks those conversations have been different. While most of America’s Middle East allies—with the exception of Israel—have publicly supported the current Iran negotiations, behind the scenes, envoys from the region have expressed grave concerns that Iran could be left with a break out capacity to make the fuel for a nuclear weapon at a time of their choosing.