Israel expects 'large scale' Iranian attack as Hezbollah evacuates its Beirut HQ as US deploys guided missile sub and aircraft carrier

 Israel is expecting a 'large scale' Iranian attack and Hezbollah has evacuated its Beirut headquarters in anticipation of an all-out war with Israel.

Israeli Defence Minister Yoav Gallant told US Defense Secretary Lloyd Austin that Iran was making preparations for a large-scale military attack on Israel during a phone call on Sunday.. 

The planned attack could happen 'within days', according to two sources who spoke to CNN. Meanwhile, Hezbollah has evacuated its headquarters in Beirut, according to Lebanese news outlet Al Joumhouria.

Hours after the call between Gallant and Austin, the US Defense Department said that Austin had ordered a guided missile submarine to the Middle East and told the USS Abraham Lincoln aircraft carrier strike group to sail more quickly to the area.

The moves come as the US and other allies push for Israel and Hamas to achieve a ceasefire agreement that could help calm soaring tensions in the region following the assassination of Hamas political leader Ismail Haniyeh in Tehran and a senior Hezbollah commander in Beirut.

Officials have been on the lookout for retaliatory strikes by both Iran and Hezbollah for the killings, and the US has been beefing up its presence in the region.

Major General Pat Ryder, Pentagon press secretary, said in a statement that Austin spoke to Gallant on Sunday, and reiterated America's commitment 'to take every possible step to defend Israel and noted the strengthening of US military force posture and capabilities throughout the Middle East in light of escalating regional tensions'.

The Lincoln, which has been in the Asia Pacific, had already been ordered to the region to replace the USS Theodore Roosevelt aircraft carrier strike group, which is scheduled to begin heading home from the Middle East.

Last week, Austin said the Lincoln would arrive in the Central Command area by the end of the month.

The carrier has F-35 fighter jets aboard, along with the F/A-18 fighter aircraft that are also on carriers.

Maj Gen Ryder also did not say how quickly the USS Georgia guided missile submarine would get to the region.

He said Austin and Gallant also discussed Israel's military operations in Gaza and the importance of mitigating civilian harm.

Israel has been braced for a major attack since last month when a missile strike killed 12 youngsters in the Israeli-occupied West Bank and Israel responded by killing a senior Hezbollah commander in Beirut.

A day after that operation, Haniyeh, the political leader of Hamas, was assassinated in Tehran, drawing Iranian vows of retaliation against Israel.

After the assassination of Hezbollah commander Shukr, the terror group reportedly moved its senior personnel away from their headquarters in Beirut - but Hezbollah now evacuated its entire operation, including its political wing, away from the suburb of Dahieh, likely in anticipation of an attack, according to Al Joumhouria. 

It comes as Israeli forces pressed on with their operations near the southern Gaza city of Khan Younis on Monday.

Palestinian medics said Israeli military strikes on several areas of Khan Younis on Monday killed at least 16 people and wounded several.