The move comes amid concerns of Iran’s response following the killings of senior Hamas and Hezbollah leaders.

United States Secretary of Defense Lloyd Austin has ordered a guided missile submarine to the Middle East and the USS Abraham Lincoln aircraft carrier strike group to sail more quickly to the area.

The order on Sunday evening followed a telephone call between Austin and Israeli Minister of Defense Yoav Galant amid mounting tensions following the killing of senior members of Hamas and the Iran-backed Hezbollah.

Austin “reiterated the United States’ commitment to take every possible step to defend Israel and noted the strengthening of U.S. military force posture and capabilities throughout the Middle East in light of escalating regional tensions”, the Pentagon said in a statement.

The USS Georgia, a nuclear-powered submarine, was already in the Mediterranean Sea in July, according to a US military post on social media, but it is rare for the US to publicly announce the deployment of a submarine.

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

Last week, Austin said it was expected to arrive in the area by the end of the month. The carrier has F-35 and F/A-18 fighter jets on board.

The US military had already said it will deploy additional fighter aircraft and warships to the Middle East as Washington seeks to reinforce Israeli defences from possible attack by Iran.

Ismail Haniyeh, the political leader of Hamas, the group that rules Gaza and is backed by Iran, was assassinated in Tehran on July 31, with Iran blaming Israel and promising to retaliate. Israel has not claimed responsibility.

The killing of Haniyeh came in the same week that Fuad Shukr, the senior military commander of the Iran-backed group Hezbollah, was killed in an Israeli attack on Beirut, leading to concerns that the conflict in Gaza might expand into a regional war.

The US announcement came a day after at least 90 people were killed and nearly 50 injured in an Israeli attack on a school-turned-shelter in Gaza, Palestinian health authorities said.

The Pentagon added that Austin and Gallant had also discussed “the importance of mitigating civilian harm, progress towards securing a ceasefire and the release of hostages held in Gaza”.

Nearly 40,000 people have been killed since Israel began its war on Gaza last October after Hamas launched a surprise attack on Israel.  An estimated 1,139 people were killed during the attack on Israel with more than 200 people taken captive by Hamas.

Washington and other allies have renewed efforts for a ceasefire.

Hamas on Sunday said the US, Qatar and Egypt should submit a plan to implement the ceasefire proposal put forward in May by US President Joe Biden, rather than holding “more rounds of negotiations” and discussing new proposals for Gaza.