The International Atomic Energy Agency says it does not know the ​status of the new Iranian enrichment facility in ‌Isfahan that is in an underground nuclear complex, agency chief Rafael Grossi said, Reuters reports.

“It is underground, but we haven’t visited it ​yet,” said Grossi, who is in Washington for a ​conference and to hold talks with Trump administration ⁠officials.

Iran informed the UN nuclear watchdog of the new facility ​in June, and Grossi said his inspectors were in Isfahan ​later that month to see it, but had to cancel the visit when the nuclear complex there was struck at the beginning of ​the 12-day war with Israel.

Grossi said because the inspectors ​had to cancel their visit, the agency does not know “whether it is ‌simply ⁠an empty hall” or hosts concrete pads awaiting the installation of centrifuges — the machines that enrich uranium for power plants and nuclear weapons — or whether some centrifuges had been ​installed.

“There are many ​questions that ⁠we will only elucidate when we are able to go back,” he said.