The United States has turned down Israeli requests for military hardware to help it prepare for a possible attack on Iranian nuclear facilities, a report in Israel's Haaretz newspaper said.

The unsourced report said the Americans had warned Israel against carrying out any such attack and had refused to supply offensive military hardware. Instead they had offered to improve the Jewish state's defences against surface-to-surface missiles.

Interviewed on Israeli Army Radio, Defence Minister Ehud Barak did not deny the Haaretz story, but refused to discuss it.

"It would not be right to talk about these things," Barak said.

The West accuses Iran of trying to develop nuclear weapons. Iran denies this and says its nuclear programme is only to generate electricity. It has vowed to retaliate against Israel and the United States if attacked.

Israel, which is believed to have the Middle East's only atomic arsenal, says a nuclear-armed Iran could threaten its existence.

The Haaretz report, by one of its senior columnists, did not specify what weapons systems Israel had requested. It said Washington had told Israel its aircraft would be denied permission to use Iraqi airspace to reach Iran.

Barak said Iran was a "threat to the whole world order, and there are many actions to be made in the realm of intelligence and preventive measures".

He said the United States "does not see an action against Iran as the right thing to do at the moment", but shared Israel's view that "no option should be removed from the table".

The United States said last week that Iran, by ignoring demands that it halt sensitive nuclear activities, had left the UN Security Council no choice but to increase sanctions.

 A spokesman for Israeli Prime Minister Ehud Olmert declined to comment on the Haaretz report but said a stronger global diplomatic push was required against Iran.

"Israel supports international efforts to place pressure on the regime in Tehran to cease nuclear enrichment. It's time for the international community to send a clear message to the Iranian leadership. Only if diplomacy is exercised seriously, will diplomacy succeed," the spokesman, Mark Regev, said.

Another Israeli official familiar with the issue, speaking on condition of anonymity, said: "The American military has made clear it doesn't want Israeli military action at this time". - Reuters