Britain, the US, France and Germany told the UN’s nuclear agency that Iran must clarify remaining questions over its nuclear program or face further action against it.

However, the four countries said an International Atomic Energy Agency resolution on the matter would only be needed if the Iranians do not comply.

“Iran cannot continue to fail to meet its legal safeguards obligations,” the group of four countries said in a Wednesday statement to the IAEA board, which is meeting in Vienna. “We urge Iran to act without delay to clarify and resolve all outstanding issues.”

Among the issues concerned are reinstalling IAEA monitoring cameras Tehran had removed from its known nuclear sites, and explaining the presence in Iran of uranium particles enriched to near weapons-grade level. “If Iran fails to implement the essential and urgent actions… the Board will have to be prepared to take further action… to hold Iran accountable in the future, including the possibility of a resolution,” the statement said.

The quartet noted it has been more than four years since undeclared nuclear material was found at undeclared locations in Iran and that in November 2022 the IAEA decided it is “essential and urgent” that Iran clarify the issues.

The countries said Iran must provide “without further delay, technically credible information” about nuclear material and contaminated equipment found at sites in Turquzabad and Varamin.

Without such explanations, the statement said, the IAEA will not be able to provide assurance that Iran’s nuclear program “is exclusively peaceful.”

“Iran persists in its deliberate refusal to engage earnestly with the Agency,” it said.

On Monday, IAEA director Rafael Grossi lamented there was a “decrease of interest” by IAEA members states regarding Iran’s nuclear program, without naming them.

The comments followed an easing tensions between Iran and the United States, which announced a prisoner swap last month.

“We are aware that there is a bilateral process of sorts. We have been informed by the United States about this. But when it comes to the nuclear part, (it is) not clear what is being discussed,” Grossi stressed at the time.

Last week, the IAEA said in confidential reports seen by AFP that Iran had made “no progress” on several outstanding nuclear issues.

In 2015, major world powers reached a deal with Iran, under which Tehran would curb its nuclear program in exchange for relief from crippling economic sanctions.