The UN's nuclear watchdog said Tuesday that it had "no credible indications" of an Iranian nuclear weapons programme.
The IAEA added that "its consideration of this issue was closed".
The statement from the International Atomic Energy Agency came a day after Israeli Prime Minister Benjamin Netanyahu offered "new proof" of a secret Iranian nuclear weapons programme, and as US President Donald Trump mulls over the prospect of pulling out of the 2015 nuclear deal signed between six Western powers and Iran.
Iran has since called Netanyahu an "infamous liar", saying Netanyahu's proof is nothing more than old news.
Iran added that Netanyahu's only aim is to influence Trump.
Iran says, and has always said, that it is not trying to build nuclear weapons. In 2015, it agreed to curb its nuclear energy programme in exchange for the lifting of sanctions.
US President Donald Trump however has for the longest time threatened to pull out of the Obama-era deal, saying it is "the worst deal ever".
Trump has repeatedly accused Iran of flouting the agreement.
He has also said that the deal's "sunset clauses" — which would see restrictions on Iran's nuclear enrichment program lifted after 2025 — are unacceptable. And he has accused Iran of not halting its ballistic missile program.