Former Mossad chief Meir Dagan warned Thursday against an Israeli attack on Iran, saying such a move would likely lead to a regional war involving Hezbollah, Hamas, and Syria.

"I'm concerned about possible mistakes and I prefer to speak out before there is a catastrophe," Dagan said in an interview on the Israeli television program “Uvda."

"I think that engaging, with open eyes, in a regional war is warranted only when we are under attack or when the sword is already cutting against our live flesh. It is not an alternative that should be chosen lightly."

Dagan stressed that though he cannot predict how many casualties an attack on Iran would yield, he said, "I have to assume that the level of destruction, paralysis of every-day life, and Israeli death toll would be high."

He said that he has no interest in hiding his fervent opposition to an Israeli attack on Iran from Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak.

Dagan said he was worried about Barak's past comments on Iran, saying Barak believes Israel has less than a year to carry out an military strike.

"I am very concerned," he said. "My understanding of Barak's comments is that Israel must act within this timeframe, but I don't believe this is accurate."

Earlier Thursday, Barak responded to comments by U.S. Joints Chiefs of Staff General Martin Dempsey, who said that he did not know whether Israel would alert the United States ahead of time if it decided to take military action against Iran.

Barak said Israel isn't looking for war with Iran and said that he would be pleased if diplomatic moves and sanctions sway Tehran away from its contentious nuclear program.

Barak's comments came after Israeli intelligence sources told the Times of London on Wednesday that a recent explosion in the western Iranian city of Ishafan was not an accident, as Iranian officials had claimed, and that the local uranium conversion plant had been damaged in the blast.

The intelligence officials told the Times that updated satellite images showed smoke billowing from the direction of the conversion plant.

According to the Israeli sources, there was "no doubt" that the blast had damaged the nuclear facility, and that the explosion was not an "accident."

"This caused damage to the facilities in Isfahan, particularly to the elements we believe were involved in storage of raw materials," one source told the Times.

Read this article in Hebrew: דגן מודאג: מדברי ברק עולה שישראל חייבת לפעול באיראן תוך פחות משנה