Story highlights Ayatollah Ali Khamenei says Iran will help anyone fighting Israel

Israel's Ehud Barak says Iran's nuclear program must be stopped

U.S. Defense Secretary Leon Panetta fears Israel may strike this spring, official says

A new report says Washington needs to put more teeth into its threats

The supreme leader of Iran issued a blunt warning Friday that war would be detrimental to the United States -- and that Iran is ready to help anyone who confronts "cancerous" Israel.

"You see every now and then in this way they say that all options are on the table. That means even the option of war," Ayatollah Ali Khamenei said during Friday prayers in Tehran. "This is how they make these threats against us.

"Well, these kinds of threats are detrimental to the U.S.," he said. "The war itself will be 10 times as detrimental to the U.S."

Khamenei's rhetoric is hardly new. But the timing of his comments could prove critical with nuclear talks around the corner.

Tensions between Iran and world powers have been ratcheted up in the aftermath of an alarming nuclear watchdog agency report in November that said Tehran was likely developing nuclear weapons.

The standoff grew more serious this week with renewed fears of an Israeli pre-emptive strike on Iran to take out its suspected nuclear weapons program.

Khamenei said Iran will support any nation or group that stands up against Israel.

"The Zionist regime is really the cancerous tumor of this region and it needs to be removed and will be removed," Khamenei said to a cheering crowd.

He said Iran doesn't interfere in other nations but has aided militant groups Hamas and Hezbollah in conflicts with Israel in Gaza and Lebanon.

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His comments came after stern comments Friday from Israeli Defense Minister Ehud Barak.

"Today, unlike in the past, there is a broad global understanding that it is crucial to stop Iran becoming nuclearized and that no options should be taken off the table," he said.

Barak said allowing Iran to continue on its path will be far more complex and dangerous in blood and money than cutting it off now.

"Those who say in English, 'later,' may find later is too late," he said.

U.S. Defense Secretary Leon Panetta said he feared Israel could attack Iran sometime this spring in an effort to destroy its suspected nuclear weapons program, according to a senior administration official.

The official declined to be identified due to the sensitive nature of the information.

The United States and its allies have warned that Iran is trying to make a nuclear weapon. Iran insists that its nuclear program is for civilian energy purposes.

A new report from the Bipartisan Policy Center said the United States needs to put more teeth into its threat to use military power against Iran.

The Washington think tank recommended in its report that Washington should undertake visible, credible military preparations to go along with more intense sanctions and diplomatic efforts.

The military activities could include naval deployments, military exercises and positioning supplies in the region.

To stop Iran's nuclear clock, the report said, the United States "needs to make clear that Iran faces a choice: it can either abandon its nuclear program through a negotiated arrangement or have its program destroyed militarily, by the United States."

The report also said the United States should give credibility to the Israeli military threat against Iran by selling Israel two to three KC-135 aerial refueling tankers and 200 GRU-31 bunker-buster munitions.

Former Sen. Chuck Robb, who co-chaired the task force that wrote the report, said the group advocates neither war nor a military strike at the moment, but believes the United States will only be effective if it takes credible steps to let Iran know it is serious.

Pentagon spokesman Capt. John Kirby said Panetta "has made it clear that he is comfortable with the military capabilities we have and operate in the region."

However, Kirby said, "the U.S. military must and will be ready to provide the president options should those options be desirable."

Khamenei blamed Western powers for Iran's troubles, starting with the brutal eight-year war Iran fought with Saddam Hussein's Iraq in the 1980s and continuing with the latest round of punishing international sanctions.

"So far we have overcome all these challenges and none of them managed to bring (Iran) to its knees," Khamenei said. "We have stood firm and strongly treaded our course."