U.S. and Iranian officials confirmed Thursday that no American nuclear inspectors will be permitted to enter the country’s contested nuclear site under the parameters of a deal reached with world powers this week, according to multiple statements by American and Iranian officials.

Under the tenants of the final nuclear deal reached this week in Vienna, only countries with normal diplomatic relations with Iran will be permitted to participate in inspections teams organized by the International Atomic Energy Agency (IAEA).

The revelation of this caveat has attracted concern from some analysts who maintain that only American experts can be trusted to verify that Iran is not cheating on the deal and operating clandestine nuclear facilities.