The UN nuclear agency's board criticized Iran for not fully cooperating with investigations and barring experienced inspectors.
A week prior, the IAEA reported that Iran had increased its stockpile of near-weapons-grade uranium.
The resolution, which received support from 20 members, sets the stage for increased tensions between Iran and the agency.
Russia and China opposed the resolution, while 12 abstained and one did not vote.
Iran has previously reacted strongly to similar resolutions.
Anonymous sources described a non-binding resolution passed at the International Atomic Energy Agency (IAEA) board, initiated by France, Germany, and Britain.
The resolution calls on Iran to implement a March 2023 joint statement, where Iran pledged to address concerns about undeclared nuclear activity and allow further verification.
Inspectors found traces of processed uranium at two Iranian sites, and the IAEA urged Iran to provide credible answers about the origin and location of the material to ensure a peaceful nuclear program.
The International Atomic Energy Agency (IAEA) has identified two sites, Turquzabad and Varamin, where it has lingering questions about Iran's nuclear program.
The Varamin site is believed to have been used as a pilot project to process uranium ore into gas form from 1999 to 2003.
Buildings at the site were demolished in 2004, and the IAEA suspects that Iran moved some material from Varamin to Turquzabad during the demolition.
Iran maintains that its nuclear program is peaceful, but the West and the IAEA believe Iran had a military nuclear program until 2003.
The IAEA is pressing Iran for full cooperation to resolve these unanswered questions, and the IAEA's director-general may need to prepare a comprehensive assessment if Iran continues to fail to provide necessary information.
In November 2022, the International Atomic Energy Agency (IAEA) censured Iran for violating nuclear agreements.
In response, Iran began enriching uranium to 60 percent purity at its Fordo nuclear plant, which is close to weapons-grade levels of 90 percent.
Previously, Iran had removed IAEA cameras and monitoring equipment from its nuclear sites in June 2022 and barred several experienced UN inspectors from monitoring its program in September.
These actions significantly hindered the IAEA's ability to oversee Iran's nuclear activities effectively.
Under a 2015 deal, Iran agreed to limit uranium enrichment for nuclear power generation in exchange for sanctions relief, with UN inspectors monitoring the program.
Tensions between Iran and the International Atomic Energy Agency (IAEA) have escalated since 2018, when the United States, under President
Donald Trump, unilaterally withdrew from the nuclear deal.
In response, Iran abandoned the restrictions the deal placed on its nuclear program and increased enrichment activities.