While no reason was given for the timing of the offer, it comes just weeks before Iran and the six powers follow up on recent talks that ended with agreement on little else but to meet again.
The new round between Tehran, and the permanent UN Security Council members the US Russia, China, Britain, France plus Germany, is tentatively set for Istanbul, Turkey in late January.
It is meant to explore whether there is common ground for more substantive talks on Iran’s nuclear program, viewed by the US, and its allies as a cover for secret plans to make nuclear arms something Tehran denies.
Instead, the Islamic Republic insists its uranium enrichment and other programs are meant only to generate fuel for a future network of nuclear reactors.
Diplomats from delegations at the table with Iran during the December talks in Geneva said Tehran made no commitments to talking about UN Security Council demands that it freezes uranium enrichment which can turn out both fuel and fissile warhead material.
And Iranian negotiators flatly ruled out discussing such demands at the Istanbul meeting.
International worries are great because Tehran developed its enrichment program clandestinely and because it refuses to cooperate with the UN’s International Atomic Energy Agency probe meant to follow up on suspicions that it experimented with components of a nuclear weapons program. Tehran denies such work.
The offer of a visit comes more than three years after six diplomats from developing nations accredited to the IAEA visited Iran’s uranium ore conversion site at Isfahan, which turns raw uranium into the gas that is then fed into enriching centrifuges.
Participating diplomats then told reporters they could not make an assessment of Iran’s nuclear aims based on what they say at that facility in central Iran.
But the new offer appeared more wide ranging, both as far as nations or groups invited and sites to be visited.
Dated Dec 27, the four paragraph letter offered no details beyond offering an all-expenses paid “visit to Iran’s nuclear sites.”