The chief U.N. nuclear inspector said Thursday that his agency's Syria probe has been hampered because key satellite images of an alleged nuclear reactor bombed by Israel are inexplicably unavailable on the market.

International Atomic Energy Agency chief Mohamed ElBaradei did not point any fingers in the "baffling" failure of his agency's efforts to obtain the images of the Syrian site hit last year by Israel immediately after the bombing.

But diplomats familiar with the IAEA's Syria probe said agency officials were considering two scenarios — that either Syria had bought the photos as part of its cover-up or that seven nations with commercial satellite networks covering the area struck had ordered them withdrawn.

One of the diplomats said the five U.N. Security Council nations — the U.S., Russia, China, France and Britain — were among the seven countries that had such networks. Both diplomats who spoke on the issue asked for anonymity because of the sensitive nature of the allegations.

Another suggested the comments by ElBaradei were at least partially out of date. He said the agency had "very recently" been able to locate commercial images showing the site after the Israeli strike.

All of the diplomats asked for anonymity in exchange for speaking to The Associated Press because their information was privileged.

ElBaradei's comments at the start of a two-day full meeting of the IAEA's 35-nation board partially reflected the focus of the gathering — Syria and Iran and suspicions about their nuclear activities.

"For its assessment of the site immediately after the bombing, the agency was unable to obtain commercial satellite imagery," ElBaradei told the meeting. "It is regrettable, and indeed baffling, that imagery for this critical period ... was not available."

An IAEA report last week drew on what satellite imagery was available and other information in suggesting the bombed site was a nuclear reactor, adding that agency inspectors had found traces of processed uranium on location. The U.S. says the target was a nearly completed reactor built with North Korean help that would have produced plutonium, a possible fissile warhead component.

Syria denies running a secret nuclear program. It has signaled it will not permit IAEA inspectors to return to the country after their initial visit to the bombed site in June, despite repeated agency requests for renewed access both to the facility hit by Israel and initial visits to three others allegedly linked to the bombed structure.

If on-ground inspection is barred by the Syria, satellite images become even more important in the IAEA probe.

ElBaradei, in comments to the closed meeting made available to reporters, also repeated criticism of Israel — for bombing the site — and the U.S. for waiting months before providing his agency with intelligence backing up its allegations of a secret Syrian nuclear program.

"The agency was severely hampered in its assessment by the unilateral use of force and by the late provision of information about the destroyed building," he said. The Israeli attack contributed to making the results of the Syria probe "inconclusive" so far, added ElBaradei.