Diplomats say talks this week between Syrian officials and top U.N. nuclear inspectors yielded no immediate breakthrough in the probe into Syria's suspected nuclear sites.
One of the diplomats, who spoke to Western media on the condition of anonymity, says Syria denied a request by inspectors from the International Atomic Energy Agency to visit the Dair Alzour complex in the Syrian desert.
The IAEA has been seeking access to Dair Alzour, which Syria claims is a non-nuclear site.
The complex was destroyed when it was bombed by Israeli jets in 2007. U.S. intelligence reports say it was a nascent, North Korean-designed reactor intended to produce plutonium for nuclear bombs.
Earlier this year, the IAEA voted to report Syria's covert construction of the Dair Alzour complex to the U.N. Security Council for possible punitive action.
The IAEA board rebuked Syria for three years of stonewalling investigators trying to visit and collect information about the Dair Alzour site.
Some information for this report was provided by AP and Reuters.