The USS Florida entered the region and began transiting the Suez Canal. File photo

US Defence Secretary Lloyd Austin has ordered a guided missile submarine to the Middle East and is telling the USS Abraham Lincoln aircraft carrier strike group to sail more quickly to the area, as the US on Monday said it believes Iran or its proxies may launch a strike against Israel as soon as this week.

The moves, announced by the Defence Department on Sunday, come as the US and other allies push for Israel and Hamas to achieve a cease-fire 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.

John Kirby, the White House national security spokesman, said Iran's response to the killings "could be this week,” but that "it is difficult to ascertain at this particular time if there’s an attack by Iran or its proxies what it could look like.” He said the U.S. and its allies were preparing for a "significant set of attacks."

Lloyd Austin speaks during a press conference. File photo

"The president is confident that we have the capability available to us to help defend Israel should it come to that," Kirby said, adding, "Nobody wants to see it come to that.”

Maj. Gen. Pat Ryder, Pentagon press secretary, said in a statement that Austin spoke with Israeli Defense Minister Yoav Gallant earlier in the day, 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.”

A joint statement from the leaders of the United States, Britain, France, German and Italy "called on Iran to stand down its ongoing threats of a military attack against Israel and discussed the serious consequences for regional security should such an attack take place.”

Associated Press