The statement from the UN watchdog comes a day after Israeli prime minister unveiled what he called "proof" that Iran's nuclear weapons programme could be reactivated at any time.
The UN's nuclear watchdog reiterated on Tuesday it had "no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009," citing its assessments from 2015.
A spokesman for the International Atomic Energy Agency (IAEA) said in a statement that its board of governors had "declared that its consideration of this issue was closed" after it was presented with a report in December 2015.
On Monday, Israeli Prime Minister Benjamin Netanyahu unveiled what he said was new "proof" that Iran's nuclear weapons programme could be reactivated at any time.
Netanyahu's televised presentation came as US President Donald Trump considers whether to pull out of the 2015 atomic accord between Tehran and six world powers.
TRT World 's Ben Tornquist reports.
IAEA evaluates all information
Without referring to Netanyahu's claims directly, the IAEA spokesman said the agency "evaluates all safeguards-relevant information available to it".
"However, it is not the practice of the IAEA to publicly discuss issues related to any such information," he added.
In the statement the IAEA pointed to its previous findings relating to Iran's activities before 2009.
"Before the end of 2003, an organisational structure was in place in Iran suitable for the coordination of a range of activities relevant to the development of a nuclear explosive device," the statement says.
"Although some activities took place after 2003, they were not part of a coordinated effort," it said, adding that "these activities did not advance beyond feasibility and scientific studies, and the acquisition of certain relevant technical competences and capabilities."
TRT World 's Jon Brain reports from Washington, DC.
CIA chief says Israeli documents 'authentic'
The documents released by Israel on Monday were "authentic," according to US Secretary of State Mike Pompeo, who until last week was the director of the CIA.
As he returned from a trip to meet Netanyahu, Pompeo said much of the information they contained was new to American experts.
In an elaborate televised presentation that included props, video and slides, Netanyahu accused Iran of lying about its nuclear ambitions, but he did not provide evidence that Israel's main enemy had actively worked to obtain an atomic weapon since the 2015 agreement between Tehran and six world powers.
Iran has always denied it sought a nuclear weapon, insisting its atomic programme was for civilian purposes.
White House press secretary Sarah Sanders said that the Iran nuclear deal was reached under false pretenses because the country's nuclear programme was more advanced than Iran indicated at the time the deal was negotiated in 2015.
"The problem is the deal was made on a completely false pretense. Iran lied on the front end," Sanders said at a regular White House briefing.
"They were dishonest actors and so the deal that was made was made on things that were not accurate. Particularly the fact that Iran's nuclear capability were far more advanced and further along than they indicated."
'The boy who cried wolf'
Iranian Foreign Minister Mohammad Javad Zarif reacted to the latest claims by lambasting both Netanyahu and US President Donald Trump, who has a May 12 deadline to decide whether to walk away from the nuclear deal.
Zarif said Israel's accusations on Tehran's nuclear programme were "old allegations" that had been dealt by the United Nations nuclear watchdog in the past.
In a tweet, Zarif dismissed Israeli Prime Minister Benjamin Netanyahu as "the boy who cried wolf," and called his presentation propaganda.
Hours after Netanyahu's claims, Trump said the presentation and other recent events showed that Trump had been "100 percent right" about Iran.
Speaking in the Rose Garden, alongside visiting Nigerian President Muhammadu Buhari, Trump said he watched part of Netanyahu's presentation and that it was "good."
Trump said Iran's behaviour was "just not an acceptable situation." He pointed to missile tests, saying Iran was "not sitting back idly."
He has declined to say whether he would withdraw the US from the 2015 nuclear deal. But he said if the US did pull out, he still might negotiate a "real agreement."
"This is an agreement that wasn't approved by too many people. And it's a horrible agreement for the United States," he said.
While most world powers say the deal is working as intended for now and is the best way to keep Iran from acquiring the bomb, Trump has been threatening to pull out for months.
'Great intelligence achievement'
Netanyahu, speaking in Tel Aviv, said Israel had recently obtained tens of thousands of files in a "great intelligence achievement," saying they had been moved to a secret compound in Tehran in 2017 that looked dilapidated from the outside.
The material obtained weighed a half a tonne, he said, speaking in the staged presentation in front of a bookcase laden with binders he said held copies of original documents and cases of CDs.
"We're going to show you Iran's secret nuclear files," Netanyahu said.
He then laid out what he said was a years-old secret nuclear weapons programme stored away that could be put into action at any time.
The details have been shared with the United States and would also be given to other countries and the International Atomic Energy Agency (IAEA), he said.
EU, Britain shun allegations
The European Union (EU) and Britain on Monday said the International Atomic Energy Agency (IAEA) remained the key to ensuring that Iran's nuclear programme was used for peaceful purposes.
Through a spokesman, Britain said it has never been naive about Iran's nuclear programme, and inspections by the IAEA were vital to ensure it is used for peaceful means.
"We have never been naive about Iran and its nuclear intentions. That is why the IAEA inspection regime agreed as part of the Iran nuclear deal is one of the most extensive and robust in the history of international nuclear accords," the spokesman said in a statement.
"It remains a vitally important way of independently verifying that Iran is adhering to the deal and that Iran's nuclear programme is exclusively peaceful."
The EU's foreign affairs chief said Netanyahu's latest allegations that Tehran once pursued nuclear weapons did not appear to show Iran was currently violating the nuclear agreement.
Federica Mogherini said in a first reaction that "what I have seen from the first reports is that Prime Minister Netanyahu has not put into question Iran's compliance" of the deal.
She insisted it was "first and foremost" the IAEA that must make the assessment whether Iran was abiding by the deal.
She said that was because "the IAEA is the only impartial, international organisation that is in charge of monitoring Iran's nuclear commitments."
'Iran had a robust weapons programme'
The White House underscored the US policy that "Iran must never have nuclear weapons" in a statement about Netanyahu's speech.
"These facts are consistent with what the United States has long known: Iran had a robust, clandestine nuclear weapons programme that it has tried and failed to hide from the world and from its own people," it said.
Supporters of the Iran nuclear deal have argued that Netanyahu's intelligence release deals simply with a historic Iranian programme and did not prove they are in breach of the 2015 accord.
But Pompeo argued that it helped to "spell out the scope and scale of the programme that they undertook" in Iran.
He said Trump would have to determine whether the United States felt Iran was in violation of the deal, and said US translators and analysts were still trawling through the intelligence provided by the Israelis.
Trump and his Middle East allies argue that the agreement, approved by Barack Obama, was too weak and needs to be replaced with a more permanent arrangement and supplemented by controls on Iran's missile programme.
French President Emmanuel Macron and Chancellor Angela Merkel of Germany left Washington last week after talks with Trump that failed to secure any promise to keep the deal alive.
Presentation provides 'nothing new'
Rob Malley, a former Obama administration official, tweeted that "for those who have followed the Iranian nuclear file, there is nothing new in [Netanyahu's] presentation."
"All it does is vindicate need for the nuclear deal. But the Israeli prime minister has an audience of one: Trump. And he's unfortunately unlikely to reach the same conclusion."
For those who have followed the Iranian nuclear file, there is nothing new in Bibi's presentation. All it does is vindicate need for the nuclear deal— Rob Malley (@Rob_Malley) April 30, 2018
But the Israeli prime minister has an audience of one: Trump
And he's unfortunately unlikely to reach the same conclusion.
Under the JCPOA (Joint Comprehensive Plan of Action) – signed by Iran, the US, Britain, China, France, Germany and Russia – Tehran agreed to curbs on its nuclear programme in exchange for the lifting of crippling economic sanctions.
The US could withdraw from the deal completely on May 12 – the next deadline for waiving Iranian sanctions.