The International Atomic Energy Agency (IAEA) says it has "no credible" evidence Iran was working on developing a nuclear "explosive device" after 2009 and that the UN's nuclear watchdog considered the issue "closed" after it was presented in a report in December 2015.

The 2015 report "stated that the agency had no credible indications of activities in Iran relevant to the development of a nuclear explosive device after 2009. Based on the director-general's report, the board of governors declared that its consideration of this issue was closed," the IAEA said in a statement on May 1.

"In line with standard IAEA practice, the IAEA 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," it added.

The IAEA statement comes after Israeli Prime Minister Benjamin Netanyahu said on April 30 that Israel had documents that showed new "proof" of an Iranian nuclear-weapons plan that could be activated at any time.

Under an agreement in 2015 with world leaders, Iran curbed its enrichment of uranium for nuclear fuel to ease concerns it could be put to use in developing bomb material. In return, Tehran won relief from most international sanctions.

Since then, UN nuclear inspectors have repeatedly reported that Iran is heeding the terms of the deal.

European states have dismissed the significance of documents, while the United States welcomed them as evidence of Iranian "lies."

Iran has accused Netanyahu of being an "infamous liar" over the allegations, which come as the United States is considering whether to pull out of an atomic accord with Tehran, which has always rejected allegations that it sought a nuclear weapon, insisting its atomic program was solely for civilian purposes.

"The documents show that Iran had a secret nuclear-weapons program for years" while it was denying it was pursuing such weapons, U.S. Secretary of State Mike Pompeo said late on April 30 as he returned to Washington from a trip to Europe and the Middle East.

"What this means is [Iran's 2015 nuclear deal with world powers] was not constructed on a foundation of good faith or transparency. It was built on Iran's lies," Pompeo said, adding that the trove of documents Israel said it obtained on Iran's so-called Project Amad to develop nuclear weapons before 2004 contain "new information."

"The Iranians have consistently taken the position that they've never had a program like this. This will belie any notion that there wasn't a program," Pompeo said.

Netanyahu made his dramatic announcement less than two weeks before the May 12 deadline for U.S. President Donald Trump to decide whether he will withdraw from the deal, which requires Iran to curb some of its nuclear activities in exchange for sanctions relief.

Reuters reported on May 1 that according to a senior Israeli official, Netanyahu informed Trump about the evidence during a meeting in Washington on March 5 and that the U.S. president agreed Israel would publish the information before the May 12 deadline.

The White House on May 1 said the United States "certainly supported" efforts by Netanyahu to release intelligence about Iran's nuclear program.

In a May 1 interview with CNN, Netanyahu said he did not seek war with Iran, but it was Tehran "that's changing the rules in the region."

Iranian Foreign Ministry spokesman Bahram Qasemi said in a statement on May 1 that accusations Tehran lied about its nuclear ambitions were "worn-out, useless, and shameful" and came from a "broke and infamous liar who has had nothing to offer except lies and deceits."

"How convenient. Coordinated timing of alleged intelligence revelations," Iranian Foreign Minister Mohammad Javad Zarif said on Twitter, adding that the Israeli claims were "ridiculous" and "a rehash of old allegations."

'This Shows Why Deal Needed'

European powers also said they were not impressed by the nearly 55,000 documents that Netanyahu claimed would prove that Iran once planned to develop the equivalent of "five Hiroshima bombs to be put on ballistic missiles."

"We have never been naive about Iran and its nuclear intentions," a British government spokesman said, adding that that was why the nuclear agreement contained a regime to inspect suspected Iranian nuclear sites that is "one of the most extensive and robust in the history of international nuclear accords."

"It remains a vitally important way of independently verifying that Iran is adhering to the deal and that Iran's nuclear program is exclusively peaceful," the British spokesman said.

Britain, France, and Germany are the three European powers that signed the deal, along with Russia, China, and the United States.

European officials said the documents provided by Israel contained no evidence that Iran continued to develop nuclear weapons after the 2015 deal was signed, so they indirectly confirm that Iran is complying with the deal.

France's Foreign Ministry said on May 1 that the Israeli information could be a basis for long-term monitoring of Tehran's nuclear activities, as the information proved the need to ensure the nuclear deal and UN inspections remained.

A German government spokesman said Berlin will analyze the materials provided by Israel, but added that the documents demonstrate why the nuclear deal with its mandatory inspections must be maintained.

"It is clear that the international community had doubts that Iran was carrying out an exclusively peaceful nuclear program," the spokesman said. "It was for this reason the nuclear accord was signed in 2015."

Netanyahu also spoke with Russian President Vladimir Putin on April 30, who afterward said in a statement issued by the Kremlin that the nuclear deal remains of "paramount importance to international stability and security, and must be strictly observed by all its signatories," the Russian state-run news agency TASS reported.

The White House welcomed the Israeli announcement, saying that Tel Aviv had uncovered "new and compelling details" about Tehran's efforts to develop "missile-deliverable nuclear weapons."

"The United States has long known Iran had a robust, clandestine nuclear-weapons program that it has tried and failed to hide from the world and from its own people," the White House said.

The jousting over the Israeli announcement came as Trump repeated his strong opposition to the deal, which he called a "horrible agreement."

"In seven years, that deal will have expired and Iran is free to go ahead and create nuclear weapons," Trump said at the White House. "That is not acceptable."

Many observers have concluded that Trump will move to withdraw the United States from the nuclear deal on May 12.

Trump did not say on April 30 what he will do, but he rejected a suggestion that walking away from the Iran deal would send a bad signal to North Korea as it negotiates with Washington over the denuclearization of the Korean Peninsula.

"I think it sends the right message" to Pyongyang, Trump said.

With reporting by AP, AFP, dpa, and Reuters