"I don`t want to get into secure information but my expectation is sooner than later," Biden told reporters when asked how imminent an Iranian attack on Israel would be

As has been reported globally, Tehran vowed revenge after Israel launched airstrikes on the Iranian embassy in the Syrian capital, Damascus, taking out three top military generals

On his message to Iran at this time, the US President said, "Don`t"

In response to more shouted questions from reporters in the White House, asking if American troops were at risk, Biden returned to the podium saying that the United States was `devoted` to the defence of Israel, CNN reported

"We are devoted to the defence of Israel. We will support Israel we will help defend Israel and Iran will not succeed," Biden said

The US has been on high alert for a significant Iranian retaliatory attack on Israel in recent days, as fears grow of a wider regional war

There remains a "real, credible and viable" threat of Iran launching strikes, the White House said on Friday, following Israel`s attack on an Iranian diplomatic compound in Syria last week, killing three Iranian generals

Biden, who warned this week that Iran was threatening a `significant attack` on Israel, has been receiving constant updates on the situation from his national security team

The US and several other countries, including India, Britain and France, issued new travel guidelines for government employees in Israel as the Iranian threat loomed