VIENNA: The UN atomic watchdog has found further uranium particles, as well as traces of graphite at a remote desert site in Syria, which the US alleges was a covert nuclear reactor.

UN inspectors detected more unexplained uranium particles at Al-Kibar, the International Atomic Energy Agency said in a restricted report.

And a senior official close to the agency revealed for the first time that particles of graphite had also been found at the site, but that it was too early to determine whether it was nuclear-grade graphite.

Graphite is used as a key element in the core of nuclear reactors.

Syria insists Al-Kibar is a disused military facility, razed to the ground by Israeli bombers in September 2007.

The IAEA visited the site, which is also known as Dair Alzour, last June, taking a series of environmental samples to see whether there were any traces of nuclear chemicals that would back up the US allegations.

Already last year, the watchdog had revealed that a “significant” number of particles of man-made uranium had been found.

But in the restricted report circulated to IAEA member states yesterday, the agency said that new analyses “have revealed additional particles of anthropogenic (man-made) uranium.” There were now around 80 uranium particles in all “of a type not included in Syria’s declared inventory of nuclear material,” the report said.

Damascus has said in the past that any uranium there could have been from the Israeli bombs that flattened Al-Kibar.

But the IAEA has virtually ruled out that interpretation.

The IAEA’s “current assessment is that there is a low probability that the uranium was introduced by the use of missiles,” it wrote.

On Iran, the report said the country has considerably slowed down the expansion of its contested uranium enrichment program. It said Iran had increased the number of centrifuges refining uranium, a process that can produce fuel for civilian energy or potentially for atom bombs, by only 164 from 3,800 in November, an insignificant change.

The report also said Iran had refused to let IAEA inspectors conduct a design check at its Arak heavy water reactor project in January and had built a dome over it, preventing satellites from taking images of the facility.

More broadly, the report said Iran was still boycotting IAEA investigators looking into intelligence allegations of past covert atom bomb work by Tehran, with the stalemate now more than six months old.

As long as Iran continued to withhold documentation, permission to interview relevant Iranian officials and visits to sites in question, it said, the IAEA would be unable to verify whether Iranian nuclear activity was peaceful or not.