Five former members of President Obama’s inner circle of Iran advisers have written an open letter expressing concern that a pending accord to stem Iran’s nuclear program “may fall short of meeting the administration’s own standard of a ‘good’ agreement” and laying out a series of minimum requirements that Iran must agree to in coming days for them to support a final deal.

Several of the senior officials said the letter was prompted by concern that Mr. Obama’s negotiators were headed toward concessions that would weaken international inspection of Iran’s facilities, back away from forcing Tehran to reveal its suspected past work on weapons, and allow Iranian research and development that would put it on a course to resuming intensive production of nuclear fuel as soon as the accord expires.

The public nature of the announcement by some of Mr. Obama’s best-known former advisers, all of whom had central roles in the diplomatic, intelligence and military efforts to counter Iran’s program, adds to the challenge facing Secretary of State John Kerry as the negotiations head toward a deadline of next Tuesday.