But Tehran has not done so, according to the diplomats, stoking tensions between Washington and Tehran.
Reuters first reported in April that the IAEA, which is policing the nuclear deal, had inspected the site - a step it had said it takes "only when necessary" - and environmental samples taken there were sent off for analysis.
Iranian President Hassan Rouhani said this week that Iran would set aside the accord's restrictions on nuclear-related research and development and would expand its use of advanced centrifuges.
"The evaluations regarding the absence of. nuclear material and activity in Iran remain ongoing", Feruta said.
One diplomat said the uranium was not highly enriched, meaning it was not purified to a level anywhere close to that needed for weapons. "We are capable inside the country to increase the enrichment much more beyond that".
In his speech, Netanyahu highlighted the regime's control of the Strait of Hormuz, which continues to be a means for control for Iran as it continues to seize and deter vessels passing through the vital waterway. A cascade is a group of centrifuges working together to more quickly enrich uranium. Iran has warned that if the nuclear deal continues to unravel, it will do just that.
"If Europeans want to make any decision, they should do it soon", he said. Iran is trying to pressure Europe to find a way to ease the economic toll of the U.S. sanctions. Another trade mechanism proposed by Europe called INSTEX also has faced difficulty.
The IAEA has told member states that Iran has had two months to answer its questions, though it has only given a very general description of the issue because it is confidential, diplomats who attended a briefing by its inspections chief last week said.
The International Atomic Energy Agency (IAEA) said in a statement that on September 7 it had "verified that the following centrifuges were either installed or being installed...: 22 IR-4, one IR-5, 30 IR-6 and three IR-6s".
He said the facility was discovered in the records Israel says it seized from an Iranian nuclear warehouse early past year. It did not elaborate.
In Paris, U.S. Defence Secretary Mark Esper said Iran's announcement wasn't a surprise.
Iran says its nuclear ambitions have always been peaceful.
"We can not remain in the deal unilaterally", he said.
Cornel Feruta, the IAEA's acting director-general, met Iranian officials on Sunday.
"There are confidential conversations among the partners about the specific details", Breul said.
Mandelker then noted that Iranian oil sales have taken a "serious nose dive" because of US pressure.
Images obtained by The Associated Press from Maxar Technologies appeared to show the Adrian Darya-1, formerly known as the Grace-1, some 2 nautical miles (3.7 kilometres) off Syria's coast. Iranian officials were not available to comment. Authorities in Tehran earlier said the 2.1 million barrels of crude oil onboard had been sold to an unnamed buyer.
The new images matched a black-and-white image earlier tweeted by John Bolton, the USA national security adviser.
"Anyone who said the Adrian Darya-1 wasn't headed to #Syria is in denial", USA national security adviser John Bolton said on Twitter on Friday, along with an image he said showed the tanker along Syria's coast. "We can talk, but #Iran's not getting any sanctions relief until it stops lying and spreading terror!"
American military leaders made guesses about whether the Israelis might choose a time of the month when the light was higher or lower, or a time of the year when sandstorms occur more or less regularly.
Gambrell reported from Dubai, United Arab Emirates. On Wednesday, the US imposed new sanctions on an oil shipping network it alleged had ties to the Guard and offered up to $15 million for anyone with information that disrupts its paramilitary operations.