By Sylvia Westall and Fredrik Dahl
VIENNA (Reuters) - The head of the U.N. nuclear watchdog took a swipe at Israel on Monday for "allegedly" bombing to rubble a suspected Syrian reactor site in 2007, saying the case should have been reported to his agency instead.
The International Atomic Energy Agency (IAEA) has been investigating Syria for three years over possible undeclared nuclear activity at the Dair Alzour site in the desert.
U.S. intelligence reports said it was a nascent North Korean-designed reactor intended to make bomb-grade plutonium.
The IAEA board is expected to rebuke Syria later this week for carrying out covert atomic work, but a Western push to refer it to the U.N. Security Council appears to have failed to win backing from several states.
Diplomats said those expressing doubt about this step against Syria -- which is also facing Western sanctions over its violent crackdown on pro-democracy protests -- included Russia and China as well as some Arab states and developing countries.
Syria denies harboring a nuclear weapons program but has blocked access to Dair Alzour since a one-off visit of IAEA inspectors in 2008.
"It is deeply regrettable that the facility was destroyed -- allegedly by Israel -- without the agency having been given an opportunity to perform its verification role," Director General Yukiya Amano told the IAEA's 35-nation governing board.
"Rather than force being used, the case should have been reported to the IAEA," he said, according to a copy of his remarks at a closed-door session.
IAEA MEETING SET TO REBUKE SYRIA
Israel has neither confirmed nor denied bombing the site and has not formally commented on what might have been there. It is widely accepted among diplomats and IAEA officials that Israel carried out the attack.
In a memoir published last year, former U.S. President George W. Bush said Israel bombed the site after failing to persuade his administration to carry out the strike.
Amano also reiterated that the site was "very likely" to have been a nuclear reactor which Damascus should have reported to the IAEA, an assessment that opened up the possibility of a Security Council referral.
Signaling the IAEA's growing frustration, Amano said Syria had been given ample time to cooperate but had declined to do so.
"Nevertheless, we had obtained enough information to draw a conclusion. I judged it appropriate to inform member states of our conclusion at this stage as it was in no one's interest to let this situation drag on indefinitely."
In an apparent effort to fend off a Security Council referral, Syria wrote to Amano last month pledging to cooperate fully regarding Dair Alzour. It did not say how it would do this.
Amano said the IAEA had since met Syrian officials but the talks had failed to produce any firm results.
"There were not (any) concrete elements to the discussion and we have agreed to meet again after the Board of Governors meeting (on June 6-10)," he told a news conference.
Amano said that even if the Syrian nuclear file were sent to New York it would not affect his willingness to engage. "I am looking forward to working with them whatever happens," he said.
(Editing by Dan Williams)