By Steve Holland

WASHINGTON U.S. President Joe Biden leaves on Tuesday on a whirlwind trip to Israel and Jordan to get an update on Israel's war aims in its looming battle with Hamas militants and stress the need to get humanitarian assistance to Gaza civilians.

Biden is expected to spend part of Wednesday in Tel Aviv for talks with Israeli Prime Minister Benjamin Netanyahu and other officials as Israel prepares a ground offensive aimed at eliminating Hamas militants in Gaza who killed 1,300 people during a rampage through southern Israeli towns on Oct. 7.

Biden will then fly to Amman for talks about accelerating humanitarian assistance to Gaza.

In Amman, he will meet Jordan's King Abdullah, Egyptian President Abdel Fattah al-Sisi, and Palestinian President Mahmoud Abbas, who has long been opposed to Hamas and whose organization exercises limited self-rule in the Israeli-occupied West Bank.

Biden's second trip to a war zone this year - he visited Ukraine in February - carries some risk. His goal will be to show American solidarity with Netanyahu while trying to avoid a broader regional war involving Iran and its Lebanese ally Hezbollah and Syria.

The United States has stationed a carrier strike group in the eastern Mediterranean in a show of force for Israel and a second is on the way.

Biden also wants to avert a humanitarian calamity in Gaza where authorities say more than 2,800 people have already been killed in Israeli bombardment over the last week.

Hundreds of tons of aid from several countries have been waiting in Egypt's Sinai peninsula for days pending a deal for its safe delivery to Gaza and the evacuation of some foreign passport holders through the Rafah crossing.

"He'll make it clear that we want to continue working with all our partners in the region, including Israel, to get humanitarian assistance in and provide some kind of safe passage for civilians to get out," said White House national security spokesperson John Kirby.

Biden and Netanyahu, thrown into a wartime partnership despite deep political differences on the way forward in the Middle East, have joined forces.

Biden has given Israel full-throated support while stressing the need to head off a massive humanitarian crisis in Gaza.

Their face-to-face meeting, after holding several phone calls since the Oct. 7 attacks by Hamas, will allow Biden to privately discuss concerns and possible red lines in the coming Gaza invasion.

Biden will also get an update on the scores of hostages taken by Hamas.

The State Department has said 29 citizens of the United States were killed in the Hamas attacks in Israel, with 15 citizens and one lawful permanent resident unaccounted for.

Israel has vowed to annihilate the Hamas movement.

Biden will make clear that "Israel has the right and indeed the duty to defend its people from Hamas and other terrorists and to prevent future attacks," Secretary of State Antony Blinken told reporters after hours of talks with Israel's war cabinet in Tel Aviv.

He said Israel would brief Biden on its war aims and strategy and on how it will conduct operations "in a way that minimizes civilian casualties and enables humanitarian assistance to flow to civilians in Gaza in a way that does not benefit Hamas."

The U.S. and Israel agreed to develop a plan that will enable humanitarian aid from donor nations and multilateral organizations to reach civilians in Gaza, Blinken said.

(Reporting By Steve Holland; additional reporting by Humeyra Pamuk in Tel Aviv; Editing by Raju Gopalakrishnan)