Traces of uranium found at a Syrian site bombed by Israel last year were not sufficient evidence of nuclear activity there, the head of the UN nuclear watchdog said on Monday.

"We won't be able to reach a quick conclusion unless we have credible information," Mohamed ElBaradei, told a news conference in Dubai. "There was uranium but it does not mean there was a reactor."    

Diplomats in Vienna told Reuters earlier this month that particles of processed uranium were found in samples taken by International Atomic Energy Agency inspectors from the site in eastern Syria, and said the findings warranted further investigation before any conclusions were drawn.

Syrian Foreign Minister Walid Al-Moualem has dismissed as politically motivated the disclosures about the uranium traces and said the uranium could have come from munitions used by Israel to bomb the site in September last year.

ElBaradei said a report on Syria's alleged covert atomic activity which the IAEA will release later this week will also not be conclusive.

"The report will say that there is still a lot of work to do. (There will be) no conclusion on whether there was a reactor or not," he said.

Both Syria and Israel should cooperate with the IAEA's investigation of Syria's alleged covert programme, he said.

"We need cooperation from Syria; we need cooperation from Israel," he said. "I would still like more transparency from the Syrians," he added.

Washington, Israel's chief ally, says the site was a secret nuclear reactor that was almost complete when it was bombed by Israel, which embarked on indirect peace talks with Syria months later.

Syria says the target of the Israeli attack was a disused military building, denies it was a plutonium-making reactor under construction and says the US intelligence was fabricated. - Reuters