LONDON — Five days after Iran struck a landmark accord with world powers on its nuclear program, the International Atomic Energy Agency announced on Thursday that Tehran had invited international inspectors to visit a heavy water production plant covered by the deal — the first tangible step since the agreement was concluded.
In a speech to the 35-nation governing board of the I.A.E.A., Yukiya Amano, the head of the United Nations’ nuclear watchdog, said the invitation was for inspectors to travel to the Arak plant on Dec. 8.
While Mr. Amano did not specifically say the invitation had been accepted, he added that “all other outstanding issues” relating to the I.A.E.A.’s differences with Iran would be addressed “in subsequent steps.”
Mr. Amano visited Tehran on Nov. 11 and said he had agreed with high-ranking officials there that Iran would permit “managed access” to at least two contentious sites — the Gachin mine in Bandar Abbas and the heavy-water production plant being built in Arak, which could be used in the production of plutonium potentially for use in weapons.
But the promise of wider scrutiny did not extend to the Parchin military site southwest of Tehran, where I.A.E.A. inspectors suspect that Iran at one time tested triggering devices for nuclear weapons.
In the lexicon of nuclear scrutiny, “managed access” usually denotes ground rules allowing host countries to protect information that they consider proprietary or secret, while permitting inspectors to collect the data they require, officials said.
The watchdog has also questioned whether the Gachin mine, which produces yellowcake uranium for conversion to nuclear fuel, is linked to Iran’s military. The announcement on Thursday did not specifically mention access to the mine.
Formally, Iran’s dealings with the I.A.E.A. run on a separate track from the negotiations that produced last weekend’s agreement in Geneva between Tehran and world powers — the United States, Russia, China, France, Germany, Britain and the European Union.
But part of the deal in Geneva specifically provided for Iran not to produce fuel for the Arak plant, install additional reactor components there or put the plant into operation.
In return for curbs on Tehran’s nuclear program, the world powers promised a limited easing of the punitive international economic sanctions which have crippled the Iranian economy.
The speed with which Tehran offered access to Arak was taken by some analysts as a sign that Iran wanted to press ahead soon with implementation of the deal, which is intended as an interim accord lasting six months during which negotiators are to discuss a comprehensive settlement.
The dispute hinges around the purpose of Iran’s nuclear program, which Western leaders say is designed to acquire the technology for atomic weapons. Iran says the program is for peaceful purposes.
I.A.E.A. inspectors, who travel regularly to Iran, have not been permitted to visit the Arak site since 2011. Iranian officials say the Arak reactor is designed to produce medical isotopes.