Defense Secretary Lloyd Austin said the deployment would allow the United States "to respond more quickly" to the crisis, while the White House stressed it did not intend to put US combat forces on the ground.

National Security Council spokesman John Kirby said preparing the troops for deployment "is really about sending a signal of deterrence."

"We don't want to see this conflict escalate and widen," Kirby said on CNN. "There are no plans or intentions to put US boots on the ground in combat in Israel."

The move comes as President Joe Biden heads to Israel on Wednesday to underscore Washington's support for its close ally.

But Biden also hopes to prevent the escalating war in Gaza from spilling over into a wider Middle East conflict.

So far, the White House has seen no signs of a deepening engagement by Iran, Kirby said.

"Outside of the rhetoric..., no we haven't," Kirby said.

Israel declared war on Hamas after the Islamist group's fighters broke through the heavily fortified Gaza border on October 7, killing more than 1,400 people, most of them civilians, and taking at least 199 people hostage.

Israel has responded with air strikes that have killed around 3,000 people, also mainly civilians, according to officials in Gaza.

Israel has also imposed a crippling siege on Gaza and deployed tens of thousands of troops to the border in preparation for a ground offensive.

The United States has already deployed two aircraft carriers to the region "to deter hostile actions against Israel," Austin said last week.

US media reported the troops being readied for deployment would cover support roles, such as medical assistance and handling explosives.

As Biden prepared for his trip to Israel, Democratic Senate Majority Leader Chuck Schumer said he will be working to approve an aid package for Israel "hopefully within the next few weeks." The package will include military, humanitarian, intelligence and diplomatic help, he said.

Congress' lower chamber has been paralyzed in recent weeks as Republican lawmakers have tried and so far failed to elect a speaker after the ouster of Kevin McCarthy on October 3 by the party's hard-right faction.

"With the house in disarray, the Senate will not wait to vote on an Israeli aid package", Schumer said Tuesday on the Senate floor.