A Syrian complex bombed by Israel bore features resembling those of an undeclared nuclear reactor and Syria must co-operate more with UN inspectors, a watchdog report said on Wednesday.

The International Atomic Energy Agency report said 'significant' amounts of uranium particles were found at the site by inspectors in June but it was not enough to prove a reactor was there and further investigation was needed.

The confidential report, obtained by Reuters, said the IAEA would ask Syria to show debris and equipment it whisked away from the site after the September 2007 Israeli air raid.

Washington says the target was a nascent reactor meant to produce plutonium for atomic bombs. Syria denies this.

Syria says Israel's target was a disused military building and the uranium traces almost certainly came with the munitions used to bomb it. Damascus has also dismissed as fabricated the satellite imagery and other intelligence propelling the probe.

'While it cannot be excluded that the building in question was intended for non-nuclear use, the features of the building, along with the connectivity of the site to adequate pumping capacity of cooling water, are similar to what may be found in connection with a reactor site,' said the IAEA report, sent to its 35-nation board of governors ahead of a November 27-28 meeting.

It noted that Syria has not produced requested documentation to support its declarations about the nature of the building nor agreed to follow-up IAEA visits to three other locations seen as harbouring possible evidence linked to Israel's target.

'The agency intends to request Syria to permit the agency to visit the locations where the debris from the building and any equipment removed from (it) are, for the purpose of taking (test) samples,' the report said.

IAEA director Mohamed ElBaradei had urged Syria, the report said, to 'provide the necessary transparency including allowing visits to the requested locations and access to all available information for the agency to complete its assessment'.

The Vienna-based UN nuclear watchdog will ask Israel to provide information pertaining to Syria's remarks about the provenance of the particles of processed uranium.

The report also stressed that the investigation had been 'severely hampered by (Israel's) unilateral use of force' and by a US failure to hand over relevant intelligence until seven months after the bombing - after Syria carted off rubble, swept the area clean and erected a new building on the spot.-Reuters