The Syrian building bombed by Israel in September 2007 bore features resembling those of an undeclared nuclear reactor and Syria must cooperate more with U.N. inspectors, according to a report by the International Atomic Energy Agency (IAEA).

The report said "significant" amounts of uranium particles were found at the site by inspectors in June but that this was not enough to prove the existence of a reactor.

The confidential report, obtained Wednesday by Reuters, said the IAEA would ask Syria to show debris and equipment it whisked away from the site after the Israeli air raid.