The UN nuclear watchdog board decided on Thursday to report Syria to the Security Council for covert atomic work, a U.S.-led move coinciding with Western condemnation of Damascus' crackdown on opposition protests.
Russia and China voted against the proposal at the UN International Atomic Energy Agency (IAEA), highlighting big power divisions on the issue.
With 17 votes in favor and six against, the IAEA's 35-nation board adopted the resolution rebuking the Arab state for three years of stonewalling of an agency probe into the Dair Alzour desert site bombed by Israel in 2007.
U.S. intelligence reports have said Dair Alzour was a nascent, North Korean-designed reactor intended to produce plutonium for atomic bombs before it was bombed to rubble.
The IAEA, the Vienna-based UN atomic agency, gave independent backing to the U.S. allegation in a report last month which said it was "very likely" to have been a reactor.
The board resolution found Syria - which is also facing Western sanctions over its violent crackdown on pro-democracy protests - in "non-compliance" with its international obligations and reported the case to the Security Council.
It came a day after Britain, France, Germany and Portugal handed the council a draft resolution condemning Syria's crackdown on protesters, despite the risk of a Russian veto.
The 15-nation council in New York has the power to impose sanctions, as it has done four times over Iran's nuclear program, but diplomats don't believe that will happen any time soon in the Syrian case due to Russian and Chinese opposition.
The IAEA board has the power to refer countries to the Security Council if they are judged to have violated global non-proliferation rules by engaging in covert nuclear work.
It reported Iran to the Security Council in 2006 over its failure to dispel suspicions that it was trying to develop nuclear weapons. Tehran has since been hit with four rounds of UN sanctions over its refusal to curb sensitive nuclear work.
Syria, an ally of Iran, denies harboring a nuclear weapons program and says the IAEA should focus on Israel instead because of its presumed nuclear arsenal.