The resolution, passed by the International Atomic Energy Agency's board of governors Tuesday, brings Iran one step closer to achieving significant sanctions relief as part of a deal reached with the U.S. and five other world powers in July. The relief is conditioned in part on IAEA certification that Iran is fulfilling its commitments under the agreement.
The IAEA decision Tuesday came even though the agency acknowledged that Iran undertook "a range of activities relevant to the development of a nuclear explosive device" through 2003, and that activities didn't cease completely until 2009, around the time the international community launched talks with Iran about its program. Those nuclear weapons-related activities were banned under several U.N. Security Council resolutions.
Still, Kerry insists these findings are nothing new, and he expressed confidence in the IAEA's ability to monitor violations of the nuclear agreement reached in Vienna this summer going forward.
"This resolution allows the Board to turn its focus now to the full implementation and verification of [the nuclear deal]," Kerry said in a statement, "which prohibits the resumption of such nuclear weapons-related activities and provides comprehensive tools for deterring and detecting any renewed nuclear weapons work."
It also "makes clear that the IAEA's Board of Governors will be watching closely to verify that Iran fully implements its commitments under the JCPOA," Kerry added, using the acronym for the deal.
Not everyone in the United States shares Kerry's confidence.
The American Israel Public Affairs Committee -- a pro-Israel interest group in the U.S. -- condemned the IAEA vote.
"The IAEA is closing this file even after discovering further suspicious evidence and experiencing additional Iranian obstinacy," the group said in a statement.
The organization said the agency's decision to move on means it is "acquiescing to an incomplete accounting of Iran's past nuclear weapons activity" and in doing so "weakens the credibility of its institution and lessens the prospect that Iran will comply with the [nuclear deal] in the future."
Western negotiators, including Kerry, came under criticism for provisions in the final deal that gave the IAEA authority to mold the nuclear inspections regime in Iran privately and without input from the international community -- an arrangement panned by critics as tantamount to "secret side deals."
Tuesday's resolution is part of a broader checklist of actions the IAEA, international community and Iran need to complete to fully implement the deal. It moves Iran one step closer towards achieving major sanctions relief.