Biden says his message to Iran is 'don't': President fears Tehran will attack Israel 'sooner rather than later' and insists U.S. is 'devoted' to defending Tel Aviv as fears of war grow

President Joe Biden said on Friday he expects Iran to attack Israel 'sooner than later' and said his message to Tehran was 'don't.' 

'We are devoted to the defense of Israel. We will support Israel and help defend Israel and Iran will not succeed,' Biden said after addressing a gathering of black leaders. 

The president's ominous tone comes amid fears that Tehran could send hundreds of drones and dozens of missiles toward Israel in retaliation for an April 1 strike on a building adjacent to the Iranian embassy in Damascus, Syria. 

Asked how imminent an attack on Israel may be, Biden said he didn't want to get into classified information but 'my expectation is sooner than later.'

The U.S. has moved more forces into the Middle East to prepare for what officials believe could be an 'imminent' strike by Iran on Israel that could spark a full-scale war.

The Pentagon is beefing up its presence in the region and the USS Dwight Eisenhower has been sent into the Red Sea in a warning to Tehran and to protect American personnel should the violence spill over, multiple reports suggest.

Biden did not address whether he has moved more U.S. forces into the region but made it clear his administration will stand by Prime Minister Benjamin Netanyahu. 

Iran's Supreme Leader Ali Khamenei vowed retribution in the wake of the Damascus attack, for which Tel-Aviv has yet to take responsibility. 

Netanyahu has vowed to respond with force to any assault by Iran, leaving tensions in the Middle East on a knife-edge. 

Defense officials on Friday said they are moving 'additional assets to the area', hours after the U.S. Embassy in Jerusalem locked down it's staff. 

The USS Dwight Eisenhower would be able to intercept missiles and drones fired by Iran.

White House National Security Council spokesman John Kirby told reporters Friday that the U.S. was in 'constant communication with our Israeli counterparts about making sure that they can defend themselves against those kind of attacks.' 

He added that 'force posture changes' had been made to ensure the US is 'properly prepared' for any Iranian assault, but declined to go into detail.

The NSC spokesperson gave no details on the potential timing of such an attack, amid warnings it could happen within the next 48 hours.

'I really don't want to get into armchair quarterbacking this thing in a public way in terms of the conversations we're having or what we're seeing in the intelligence picture,' Kirby said.  

On Thursday, the U.S. embassy in Jerusalem did not explicitly mention Iran but issued a warning to government workers. 

'Out of an abundance of caution, U.S. government employees and their family members are restricted from personal travel outside the greater Tel Aviv, … Jerusalem, and Be'er Sheva areas until further notice,' the security alert read. 

The April 1 attack in Damascus killed two senior members of the Islamic Revolutionary Guard Corps and five other officers, Iran said. 

Israel has yet to claim responsibility publicly.  

The Washington Post reported Thursday that senior Pentagon officials were frustrated that the U.S. did not get a heads up from Israel before conducting an airstrike on the Iranian site. 

Three unnamed U.S. officials told the paper said Defense Secretary Lloyd Ausin and other senior defense officials believed Israel should have informed the Pentagon ahead of the attack because of the strike's implications for U.S. servicemembers in the region. 

Had the U.S. gotten a heads up, the Pentagon would have been able to heighten defense capabilities in order to withstand Iranian retaliation, the sources said. 

If Israel and Iran to engage in an all-out war, the consequences could be devastating.

Professor Gerald Steinberg, an expert in conflict management and founder of Jerusalem-based NGO Monitor, said a potential war between Iran and Israel would be both futile and devastating.

'They are on the verge of a confrontation similar to the October 1962 Cuban missile crisis between Washington and Moscow. Both countries can do massive damage to the other, but neither can 'win',' he said.

Wyn Bowen, Professor of International Security at King's College London's Department of War Studies, told DailyMail.com that it is unlikely Iran will seek to directly attack targets on Israeli soil, lest it risk an uncontrollable military response from Israel and its chief ally, the US.

But he also cautioned 'the Iranian leadership is under significant pressure to respond robustly' to the consulate attack, suggesting that a direct conflict, albeit unlikely, must be considered.