Joe Biden
Biden will hold talks in Israel and Jordan on Wednesday AFP

Joe Biden heads to the Middle East on potentially the riskiest trip of his presidency Tuesday, aiming to thread the needle between supporting Israel against Hamas, averting catastrophe in Gaza and preventing a regional war.

The US president will fly into a war zone for high-stakes talks with Prime Minister Benjamin Netanyahu in key ally Israel on Wednesday, then head to Jordan for a four-way summit with regional leaders.

The 80-year-old Biden's diplomatic drive will be one of the biggest gambles of his long career in both political and security terms, and a test of US influence in a tinderbox region.

"He's coming here at a critical moment for Israel, for the region and for the world," US Secretary of State Antony Blinken said as he announced Biden's visit during his own marathon diplomatic drive.

The New York Times called it a "trip fraught with risks".

Biden made a top-secret trip to war-torn Ukraine last year to demonstrate US support for the pro-Western country's battle against Russian invasion.

Despite frequent air raid warnings, US officials say the security threat to Biden in Israel is lower. But the political stakes on this visit are arguably far greater.

Blinken said the president wanted to show "ironclad" support for Israel after the Palestinian militant group Hamas burst through its heavily fortified Gaza border on October 7, shooting, stabbing and burning to death more than 1,400 people, most of them civilians.

The show of solidarity is especially important in US thinking amid fears that Iran or its Lebanese ally Hezbollah could get involved. Washington has sent two aircraft carriers to the region to deter them.

However, the Democratic president deliberated carefully before accepting the invitation to visit from right-winger Netanyahu, who has ordered preparations for what is expected to be a bloody ground offensive against Hamas in Gaza.

The risk is that Biden finds himself too closely associated with an Israeli invasion of Gaza, which is already being subjected to a withering campaign of air strikes that have leveled swaths of the enclave and killed more than 2,700 people.

Asked if Washington expected Israel to wait until after Biden's trip to launch any ground offensive, National Security Council spokesman John Kirby said, "we're not dictating terms or operational directions to the Israelis."

Biden's display of support for Israel also crashes against a potentially contradictory aim: ongoing US and international efforts to ease the devastating impact of the war on Palestinian civilians.

He has in recent days increased pressure on Israel to protect civilian lives from the air strikes and a siege that has left Gaza at risk of a humanitarian disaster.

"The president believes that this is exactly the right time to go to Israel and to go to Jordan," Kirby told CNN on Tuesday.

Biden will "speak to other leaders in the region, about the humanitarian assistance that we want to make sure gets into Gaza, about Israeli plans and intentions going forward," he added.

In Jordan, Biden will meet King Abdullah II of Jordan and President Abdel Fattah al-Sisi of Egypt -- the first two Arab countries to make peace with Israel -- as well as Palestinian leader Mahmud Abbas, a Hamas foe based in the West Bank.

Talks with Sisi are likely to focus on his refusal so far to open the Rafah border crossing to Palestinians massed in southern Gaza as they flee the expected Israeli invasion.

Jordan's royal court voiced hopes that the four-way summit could help "revive the peace process" between Palestinians and Israel, which has been at a standstill for years.

The world, and America's rivals like China and Russia, will be watching the results of Biden's trip closely.

The US president however has rejected questions about whether Washington would be overstretched by supporting allies at war in both Israel and Ukraine.

"We're the United States of America for God's sake. The most powerful nation in the history of the world," Biden said in an interview broadcast on the CBS News program 60 Minutes at the weekend.