Inspectors from the UN’s nuclear agency have visited a facility in Tehran that Prime Minister Benjamin Netanyahu said was an undeclared site used by Iran to house nuclear material, according to a Reuters report on Thursday.

Speaking at the United Nations in September, Netanyahu called on the International Atomic Energy Agency to inspect the “secret atomic warehouse” in the Iranian capital, which he said may be storing some 300 tons of nuclear-related equipment and material.

The speech came months after Israel’s disclosure that it had spirited away what it said was a “half-ton” of Iranian nuclear documents from Tehran, with Netanyahu saying both the archive and the warehouse were proof that Iran continues to seek atomic weapons despite the 2015 international agreement to limit its nuclear program.

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Following Netanyahu’s appearance, IAEA head Yukiya Amano said nuclear inspectors had visited “all the sites and locations in Iran which it needed to visit,” while pushing back on the prime minister’s assertion that the organization had failed to act on intelligence provided by Israel on the warehouse.

Diplomats quoted by Reuters Thursday, however, said the IAEA visited the site in Tehran’s Turquzabad district multiple times last month. They said tests were underway on environmental samples taken from the facility in order to determine if nuclear materials were present there. Results will not be ready until June.

“We have nothing to hide and any access given to the IAEA so far has been in the framework of laws and regulations and nothing beyond that,” the news agency quoted an Iranian official saying.

At the time of Netanyahu’s UN speech, Iranian state-media claimed the warehouse was actually a recycling facility for scrap metal.

Reuters said the Israeli Foreign Ministry declined to comment on the report.

Putting the coming results of the tests aside, a number of diplomats said the fact the IAEA was given access to the facility showed the 2015 deal was working, despite US President Donald Trump’s decision last year to pull out of the accord and reimpose sanctions on Iran.

“The Iranians have realized that complying with the deal is in their interests,” a diplomat told Reuters.

Netanyahu was a vocal opponent of the deal when it was signed under Trump’s predecessor Barack Obama, arguing that it would not stop but only delay Iran’s nuclear weapon program, while removing sanctions critical to curbing Tehran.

Iran for its part has denied it is seeking atomic weapons, while warning it could walk back its commitment to the nuclear accord if it does not receive economic inducements from its remaining signatories — Britain, France, Germany, Russia and China.

Agencies contributed to this report.