A secret Syrian facility built under former President Bashar Assad was configured to produce material that could have been used to make nuclear weapons, the head of the UN nuclear watchdog said Monday.

International Atomic Energy Agency chief Rafael Grossi speaks to reporters at the agency's headquarters in Vienna, Austria on Monday.International Atomic Energy Agency chief Rafael Grossi speaks to reporters at the agency's headquarters in Vienna, Austria on Monday.Close

International Atomic Energy Agency chief Rafael Grossi speaks to reporters at the agency’s headquarters in Vienna, Austria on Monday. Credit: Joe Klamar/AFP

International Atomic Energy Agency chief Rafael Grossi speaks to reporters at the agency’s headquarters in Vienna, Austria on Monday. Credit: Joe Klamar/AFP

International Atomic Energy Agency Director-General Rafael Grossi said he was not drawing conclusions about Syria’s intentions. But he said the never-completed reactor was designed to efficiently produce material “directly suitable for the manufacture of nuclear weapons.”

The IAEA is working with Syria’s transitional government to investigate the Assad-era nuclear program. IAEA experts recently secured tons of previously undisclosed uranium stocks and reactor fuel rods.

Israel destroyed the nearly completed facility in an airstrike in 2007.

A composite image taken from video released in 2018, which the Israeli military describes as an Israeli air strike on a suspected Syrian nuclear reactor site near Deir al-Zour on Sept 6, 2007.A composite image taken from video released in 2018, which the Israeli military describes as an Israeli air strike on a suspected Syrian nuclear reactor site near Deir al-Zour on Sept 6, 2007.Close

A composite image taken from video released in 2018, which the Israeli military describes as an Israeli air strike on a suspected Syrian nuclear reactor site near Deir al-Zour on Sept 6, 2007. Credit: IDF/Handout via Reuters TV

A composite image taken from video released in 2018, which the Israeli military describes as an Israeli air strike on a suspected Syrian nuclear reactor site near Deir al-Zour on Sept 6, 2007. Credit: IDF/Handout via Reuters TV

The IAEA said in 2011 that the facility at Dair al-Zour bore similarities to a reactor in North Korea, a nuclear-armed country. The agency did not then say whether the Syrian facility was intended for a military nuclear program.

Syria’s former government denied having such intentions. Assad was ousted in December 2024.

The government of transitional President Ahmed al-Sharaa has disclosed details of the former nuclear program and cooperated with the IAEA investigation.

Grossi contrasted Syria’s cooperation with Iran’s, saying Tehran has blocked IAEA cooperation for months. IAEA experts have not received explanations about the purpose of some former Iranian nuclear facilities, among other issues.

Grossi said Syria and Iran were “two different cases” and that Syria’s transparency had helped it rebuild relations with other countries.

“That should perhaps also give others something to think about,” Grossi said, referring to Tehran.