By Francois Murphy

VIENNA (Reuters) -The U.N. nuclear watchdog, which polices the global nuclear Non-Proliferation Treaty, has not been able to carry out inspections in Iran since Israel launched military strikes on its nuclear facilities on June 13.

Below is an outline of the International Atomic Energy Agency's inspection powers.

DOES THE IAEA HAVE UNIVERSAL JURISDICTION?

No. The IAEA's oversight is limited to the 191 states that are signatories to the NPT, and other countries it has separate arrangements with. Iran is a party to the NPT and thus subject to IAEA oversight including inspections meant to ensure that no nuclear material such as uranium is "diverted" for use in atomic bombs.

Israel is not a party to the NPT and is the only country in the Middle East widely believed to have nuclear weapons. Israel does not confirm or deny having them. 

It has a limited safeguards agreement with the IAEA that provides for the agency to oversee some materials and facilities - a fraction of what Israel has and not any of what is widely believed to be its nuclear weapons programme.

Iran, by contrast, has a Comprehensive Safeguards Agreement (CSA) with the IAEA under which it must account for all its proliferation-sensitive nuclear material, including every gram of enriched uranium.

CAN THE IAEA GO ANYWHERE, ANYTIME IN IRAN?

No. It is largely restricted to inspecting Iran's declared nuclear installations as provided for by its 1974 CSA - sites such as the three uranium enrichment plants at Natanz and Fordow that were operating until Israel bombed them on June 13.

It had regular access to those facilities until they were attacked. Since then, they have been "closed" and inspectors have not been allowed in, the IAEA has said, adding that it hopes its inspectors will return as soon as possible.

HAS THE IAEA HAD GREATER POWERS BEFORE?

Yes. A 2015 deal between Iran and major powers placed strict limits on Tehran's nuclear activities but also extended the IAEA's oversight to parts of Iran's nuclear programme not covered by the CSA, such as its production and stock of centrifuges, the machines that enrich uranium.

It was the most comprehensive IAEA oversight of any country.

Much of that additional oversight came from Iran agreeing, as part of the 2015 pact, to apply the Additional Protocol, an add-on to countries' CSAs that the IAEA developed to strengthen its hand in preventing nuclear proliferation. Iran has signed but never ratified the Additional Protocol.

One of the most important extra tools the Additional Protocol gives the IAEA is the power to carry out snap inspections - short-notice access to locations including ones that Iran has not declared to be nuclear-related.

WHY DOES IT NO LONGER HAVE SUCH SWEEPING POWERS?

In 2018, during his first term, President Donald Trump pulled the U.S. out of the 2015 nuclear deal, reimposing U.S. sanctions on Iran that had been lifted as part of the agreement.

In retaliation, as of the following year, Iran began pushing past the deal's limits on its nuclear activities but also scaled back the extra IAEA oversight introduced by the deal.

In February 2021 Iran said it would no longer carry out its extra commitments under the 2015 deal, including implementation of the Additional Protocol. It struck a deal with the IAEA to keep monitoring equipment like surveillance cameras added under the deal rolling, but ordered them all removed in June 2022.

WHAT WAS LOST WITH THE EXTRA OVERSIGHT?

Reducing the IAEA's oversight not only took away the important tool of snap inspections. It also left blind spots in the areas to which extra oversight had been applied.

The IAEA now says it has lost so-called "continuity of knowledge" for so many years that it will never be able to fully piece together what happened in areas including the production and inventory of centrifuges and certain key centrifuge parts, as well as Iran's stock of "yellowcake" - uranium that has not been enriched.

The fact many centrifuges are unaccounted for means it cannot be ruled out that they will be used to enrich uranium in secret at an undeclared facility. Such a facility would be easy to hide in a relatively small building such as a warehouse.

The IAEA says it cannot guarantee Iran's nuclear activity is entirely for peaceful purposes but it also has no credible indications of a coordinated nuclear weapons programme.

WHAT IF IRAN PULLS OUT OF THE NON-PROLIFERATION TREATY?

Iran has threatened to pull out of the NPT, while at the same time saying it would not develop nuclear weapons if it did. 

Tehran has complained that the treaty and non-proliferation regime failed to protect it from attack by a country with a nuclear arsenals, the United States, and another widely believed to have one, Israel.

The NPT allows for withdrawal by a party at three months' notice "if it decides that extraordinary events, related to the subject matter of this Treaty, have jeopardized the supreme interests of its country".

The only country to announce its withdrawal from the NPT is North Korea in 2003, which expelled IAEA inspectors before testing nuclear weapons. 

(Reporting by Francois Murphy; editing by Mark Heinrich)