The report said the evidence for the claim came primarily from Israel, including satellite images that led US officials to believe the facility could be used to produce material for nuclear weapons.
The new information, in particular images received by the US over the past month, has only been shared with a few senior officials, as was instructed by national security adviser Stephen J. Hadley.
Despite reports, the Washington Post said many in the intelligence community were unaware of the images, or uncertain of their significance. Intelligence sources emphasized that preliminary reports on suspicious activity are often reassessed over time and found to be inaccurate.
According to the Washington Post, some security sources expressed doubt over the possibility that Syrian was cooperating with North Korea on a nuclear site, despite the fact that the two countries have previously cooperated on the manufacture of technological missiles.
According to a New York Times report published Wednesday, a US official said that recent Israeli reconnaissance flights over Syria revealed possible nuclear installations that Israeli officials estimate might have been supplied with material from North Korea.
The report also said American officials confirmed that Israeli jets had launched an airstrike inside Syria. Sources said that Israel struck at least one target in northeastern Syria, but could not provide more details.