(CNN) -- The United Nations' nuclear watchdog agency Thursday found that Syria built a covert nuclear reactor and failed to comply with demands for information on the facility.
The International Atomic Energy Agency's strongly worded resolution referred Syria to the U.N. Security Council for further deliberation.
Syria has been repeatedly questioned over whether a nuclear facility existed at the Dair Alzour site, which was bombed by Israeli aircraft in September 2007. Syria has said it was a non-nuclear military site.
The IAEA approved the resolution with 17 in favor and six against. There were 11 abstentions and one absence.
The United States welcomed the findings and said it was step toward upholding nonproliferation rules.
"As the IAEA reports, with assistance from North Korea, Syria attempted to build a secret nuclear reactor capable of producing large amounts of nuclear weapons-usable plutonium, but with no apparent legitimate civilian purpose," the White House said in a statement. "Syria has stonewalled and obstructed the efforts of the IAEA to investigate the nuclear reactor for years, refusing to provide access to associated sites, personnel and documents in violation of Syria's freely-accepted legal obligations."
Syria claimed Israeli missiles that destroyed the building at the site were the source of uranium particles, according to an IAEA report issued in 2009.
Thursday, the IAEA said Syria's statements on the Dair Alzour site are not supported by documentation and that it has repeatedly failed to provide information.
The resolution found Syria's undeclared construction of a nuclear reactor is a breach of international agreements.