Austin will meet with officials including Prime Minister Benjamin Netanyahu and Defence Minister Yoav Gallant during the visit to Israel -- his third as Pentagon chief -- which follows one by Secretary of State Antony Blinken.

The trip is aimed at underscoring "the unwavering support of the US for the people of Israel and commitment to ensuring Israel has what it needs to defend itself", the US Defense Department said in a statement.

Austin will also personally see the delivery of some of the security assistance the United States is sending to Israel in the wake of the surprise Saturday attack by Hamas militants who killed 1,200 people in Israel and took about 150 hostages.

Israel has retaliated by raining air and artillery strikes on Hamas targets in Gaza for days, claiming at least 1,537 lives.

Washington has deployed an aircraft carrier and other warships to the eastern Mediterranean and promised munitions and other equipment to Israel.

"We have been surging support to them. Multiple shipments have arrived in Israel of materiel they requested and another one will arrive today and more over the coming days," a senior US defence official told journalists en route to Israel.

The United States was also "engaging (the Israelis) on the issue of hostages. We are giving advice and assistance on this critical issue," the official said.

Austin told journalists in Brussels on Thursday that the United States had no "early warnings or indications" that the Hamas would launch its bloody assault.

He also said the United States has not placed any conditions on the way Israel can use the weapons it provides.

"This is a professional military, led by professional leadership, and we would hope and expect that they would do the right things in the prosecution of their campaign," he said.

Israel is preparing for a possible ground invasion of the Palestinian territory after what has been labelled Israel's 9/11.

Fears have grown for Gaza's 2.4 million people now enduring the fifth war in 15 years in the coastal enclave, which has also seen Israel cut off water, food and power supplies.