U.S. President Donald Trump said on Wednesday that the damage to Iranian nuclear sites from missile strikes over the weekend was severe, though he also acknowledged that the available intelligence on the matter was inconclusive.

His comments followed reports by Reuters and other media outlets on Tuesday revealing that the U.S. Defense Intelligence Agency had assessed that the strikes had set back Iran's nuclear program by just a few months, despite administration officials saying the program had been obliterated.

"The intelligence was very inconclusive," Trump told reporters before joining a NATO summit in The Hague. "The intelligence says we don't know. It could've been very severe. That's what the intelligence suggests."

Later, during the same round of comments, Trump argued that Iran's nuclear deal had been set back "basically decades, because I don't think they'll ever do it again".

Trump was sitting alongside Secretary of State Marco Rubio and Secretary of Defense Pete Hegseth, who both also cast doubt on the reliability of the DIA assessment.

Rubio said the U.S. was opening an investigation into the leak of the DIA report. He also suggested the report's contents had been misrepresented in the media.