The UN nuclear watchdog has said it would send investigators to Iran's disputed Parchin military complex were Tehran to allow it.
The topic would be discussed at talks in the Iranian capital later this week, Agence France-Presse cited chief inspector for the International Atomic Energy Agency (IAEA) Herman Nackaerts as saying at Vienna airport on Wednesday on his way to Tehran.
"We also hope that Iran will allow us to go the site of Parchin, and if Iran would grant us access we would welcome that chance and we are ready to go."
The IAEA believes Iran has conducted nuclear tests using explosives at Parchin, a sprawling facility southeast of Tehran, and has repeatedly asked for access, Reuters reported.
According to the Tehran Times, the IAEA suspects Iran of trying to sanitize the Parchin site of any incriminating evidence.
However, Iran has called the claim "baseless" and says the IAEA has no right to inspect Parchin and refused requests by IAEA delegations to access the site during their visits to Iran from Jan. 29 to 31 and Feb. 21 to 22.
The Islamic state also denies ever having sought nuclear weapons.
Although it made two visits to Parchin in 2005, the IAEA says that work carried out there since then makes it want to go back.
And despite work apparently being undertaken to cleanse the site, IAEA chief Yukiya Amano said last week a visit would still be "useful," Reuters wote.