US Defense Secretary Lloyd Austin placed the personnel and a range of units "on a heightened state of readiness through a prepare to deploy order," the Pentagon said in a statement, to be able "to respond quickly to the evolving security environment in the Middle East."

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

"No decisions have been made to deploy any forces at this time," it added.

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

Biden will be on a mission to prevent the escalating war in Gaza from spilling over into a wider Middle East conflict.

Israeli Prime Minister Benjamin Netanyahu 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 more than 2,700 people, also mainly civilians, imposed a crippling siege on Gaza, and deployed tens of thousands of troops to the border in preparation for a full-scale ground offensive.

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