OCCUPIED JERUSALEM: Israeli Defense Minister Ehud Barak called Wednesday for major powers to speed up efforts to stop Iran's nuclear program, cautioning it would be tougher to confront it once Tehran managed to cross an atomic threshold.

Israeli media interpreted Barak's comments as pushing for a possible Israeli strike against Iran to stop a project the West sees as a drive to achieve nuclear weapons though Tehran denies seeking nuclear weapons, saying its program is intended solely for peaceful purposes.

"I am very well aware and know in depth the difficulties and complexity involved in preventing Iran from achieving nuclear weapons," Barak told a graduation ceremony for security officers, in remarks later released by his office.

"But it is clear to me beyond any doubt that confronting that (nuclear) challenge in itself once it ripens if it ripens, will be infinitely more complex infinitely more dangerous and infinitely more costly in human life and resources," he said.

"This is the time for the entire world to ready for united action, united goal in political desire in order to put a swift and definite stop to the Iranian nuclear project," Barak said.

In his lengthy remarks, Barak said Israel now faced "its most complex challenges ever", adding "we may need to make fateful and difficult decisions with regard to Israel's security," pointing also to what he called growing instability posed by popular revolts in neighboring Arab countries.

"The events of the Arab spring, which have gradually evolved into an Islamic summer, show that at the ultimate hour of decision we can rely at the moment of truth on ourselves alone," Barak said.

The Israeli news website Ynet quoted an unnamed senior official as interpreting Barak's remarks as an attempt "to push with all his might" in favor of an attack on Iran, which Prime Minister Benjamin Netanyahu's cabinet was weighing whether to launch in the coming weeks, media reports said.

Israel has cautioned it saw time as running out before Iran achieves a "zone of immunity" in which Israeli bombs cannot penetrate deeply buried uranium enrichment facilities, and that Western economic sanctions had so far not achieved a goal of stopping Iran's nuclear program.

Netanyahu's ex-deputy, Shaul Mofaz, cautioned this week, just days after quitting the Israeli cabinet in a dispute over a military conscription law, against what he called "operational adventures."

Israeli media saw Mofaz's comments as a hint of possible action against Iran. His remarks also echoed the warnings of other former Israeli security officials against any go-it-alone attack on Iran's nuclear facilities, with some saying such an assault could backfire by spurring Tehran to speed up uranium enrichment.

But the failure of talks between Iran and six world powers to secure a breakthrough in curbing what the West fears is a drive to develop nuclear bombs has raised international concerns that Israel, widely assumed to be the Middle East's only nuclear-armed state, might opt for a military strike.

Those negotiations, Netanyahu said on the Fox television news channel on Sunday, had failed to slow uranium enrichment in Iran "one bit."