Vienna, Austria ? U.N. nuclear agency samples taken from a Syrian site suspected of being a secretly built reactor have revealed new traces of processed uranium, the agency reported Thursday.

A separate report by the same organization — the International Atomic Energy Agency — noted a significant slowdown in Iran’s efforts to expand its uranium enrichment program. The U.N. Security Council has slapped sanctions on Iran for not freezing enrichment, which can be used to make both nuclear fuel and the core of warheads.

The report did not suggest a reason for the slowdown. But agency chief Mohamed ElBaradei said earlier this week the reason appeared to be “political” — indicating Iran may be waiting for conciliatory signals from the new U.S. administration, which has said it is ready to talk directly with Iran on nuclear and other disputes.

A diplomat familiar with the enrichment program suggested, however, that the reason might be technical, with the program experiencing significant breakdown of the centrifuges used to spin uranium gas into enriched material. He demanded anonymity for discussing confidential information.

Both reports — meant for restricted release Thursday only to the 35 nations of the IAEA board — were obtained by The Associated Press.