The United States asked the U.N. nuclear monitoring agency Thursday for a more complete accounting of its probe of Syria's alleged efforts to secretly develop a plutonium-producing facility at a site bombed by Israel.

A senior Syrian envoy in turn accused Washington of using "twisted logic" in pressuring his country instead of condemning the Israeli attack.

"When you shield the aggressor and when you accuse the victim it is ... being not only an accessory to the crimes committed, but also encouraging more crimes," Syrian Ambassador Mohammed Badi Khattab told The Associated Press.

He urged whatever U.S. administration takes office next year to play a more active role in Turkish-mediated Syrian-Israeli efforts to reach a peace agreement.

"Without the U.S. being in the negotiations, there is no guarantee that what you agree upon will be implemented," he said. Because the U.S. is "the only country that has this unique relationship with Israel ... (it) has the duty to influence its position in moving forward," said Khattab.

The United States has hung back from directly engaging Syria, insisting it must stop support for Lebanon's Hezbollah and other groups labeled by Washington as terrorists.

Khattab is also his country's chief delegate to the International Atomic Energy Agency. He spoke after U.S. chief representative Gregory L. Schulte suggested his country was dissatisfied with a brief oral report on the status of an IAEA probe of allegations that Syria was working on covert nuclear program that included a nearly finished reactor bombed by Israel a year ago.

"Given the gravity of the issue ... the United States looks forward to a comprehensive report ... detailing, in writing, the status of the investigation" at the November meeting of the 35-nation IAEA board, Schulte told board members, in comments to the closed meeting made available to reporters.

Detailing allegations of months of efforts by Syria to alter the Al Kibar site and rid it of any evidence it was a nuclear facility, Schulte asked: "What does Syria have to hide?"

In his oral report Monday, IAEA chief Mohamed ElBaradei told the board meeting that preliminary results from environmental samples taken in June from the bombed site came up with "no indication" to back the claims that the destroyed target was a nuclear facility.

He also said that Syria would decide on whether to provide more information and allow further IAEA visits depending "on the results of the samples taken during the first visit" — implying that Damascus could shut the doors on the probe if the all the samples come up empty.

Pressed whether Syria would permit further visits, Khattab said: "We are not opening the door, and we are not closing the door" until after the results come in.

The issue is significant because of concerns that the investigation could grind to a halt if the samples show no nuclear-related traces and Syria uses that finding to declare the probe closed.

That could cripple international efforts to probe whether the site in a remote part of the Syrian desert was a near-finished plutonium-producing reactor built with North Korean help, and that Damascus continues to hide linked facilities.

IAEA inspectors looking for unreported nuclear activity usually test for radioactivity. But in this case, their mission was more difficult.

According to intelligence given to the Vienna-based agency by the U.S., Israel and a third, unidentified country, the alleged reactor was not yet completed at the time of the Sept. 6, 2007, bombing. That meant no nuclear material would have been present.

So the inspectors looked for minute quantities of graphite, which is used as a cooling element in the type of North Korean prototype that was allegedly being built.

But — if they were interested in a cover-up — the Syrians would have scoured the region to bury, wash away and otherwise remove any such traces.