Vienna: Uranium particles found at a Syrian desert complex bombed to ruin by Israel in 2007 point to possible covert nuclear activity at the site, the UN atomic watchdog said on Thursday.

It was the first time the International Atomic Energy Agency lent public support to Western suspicions that Israel's target was a nascent nuclear reactor that Washington said was North Korean in design and geared to making weapons-grade plutonium.

Previous IAEA reports on its two-year investigation into the affair, impeded by a lack of Syrian cooperation, said only that the uranium particles raised concern because they did not come from Syria's declared inventory. "The presence of such particles points to the possibility of nuclear-related activities at the site and adds to questions concerning the nature of the destroyed building," said the confidential report by new IAEA Director-General Yukiya Amano.

"Syria has yet to provide a satisfactory explanation for the origin and presence of these particles," he wrote, dismissing Damascus's contention that the traces came with munitions used by Israel to wreck the complex.

Amano prodded Syria to adopt the IAEA's Additional Protocol, which permits unfettered inspections beyond declared nuclear site to ferret out any covert atomic activity.