The head of the United Nation's atomic watchdog again hit out at Israel's willingness to take unilateral action against countries such as Syria, in comments published in a magazine interview Monday.

As well as the build-up of nuclear arms, the increasing penchant of countries to bomb suspected nuclear facilities also posed a growing threat to world peace, IAEA chief Mohamed ElBaradei told news magazine Der Spiegel.

"With unilateral military actions, countries are undermining international agreements, and we are at a historic turning point," said ElBaradei.

He was referring to the Israel bombardment of Syria's Al-Kibar complex last September.

"We only heard of the Israeli action from the television. No-one gave us any information or informed us of their suspicions," he said.

"We were only given access to pictures of the building and its destruction at the same time as the US Congress. That is unacceptable," ElBaradei said.

ElBaradei also slammed Israel and the United States for not passing on earlier intelligence that allegedly showed the Al-Kibar site was a covert nuclear reactor.

The International Atomic Energy Agency had received "too little information too late," ElBaradei complained.

But the Egyptian-born diplomat insisted that he expected "absolute transparency" from Syria.

IAEA is sending a team of experts to Syria on June 22-24 to investigate the allegations and ElBaradei said his inspectors would demand visits to a number of locations that may have delivered components to the destroyed facility.

ElBaradei also hit out at Tehran for stonewalling the IAEA's long-running investigation into Iran's nuclear activities.

"The readiness on Iran's side to cooperate leaves a lot to be desired," he said. "We have pressing questions."

Iran's leadership, he said, was sending "a message to the entire world: We can build a bomb in relatively short time."

Last week Israeli Deputy Prime Minister Shaul Mofaz warned that his country could attack Iran if Tehran "continues with its programme to develop a nuclear bomb."

But his comments drew rebukes even from officials inside his own country.