U.S. President Joe Biden will make a high stakes visit to Israel on Wednesday to show support for its war on Hamas, after Washington said Prime Minister Benjamin Netanyahu had agreed to let humanitarian aid reach besieged Gazans.

Trucks carrying vital supplies for Gaza headed towards the Rafah crossing in Egypt, the only access point to the enclave outside of Israel's control, though it was not certain whether they would be able to cross.

A witness told Reuters some 160 trucks had set off towards the border from the nearby Egyptian town of Al-Arish, where they have been backed up waiting while diplomats tried for days to open the route.

Israel has vowed to annihilate the Hamas movement that controls Gaza after Hamas gunmen killed 1,300 people, mainly civilians, during a rampage through southern Israeli towns on Oct. 7, the deadliest single day in Israel's 75-year history.

Israel has bombarded the Gaza Strip with air strikes that have killed more than 2,800 Palestinians, a quarter of them children, and driven around half of the 2.3 million Gazans from their homes. It has imposed a total blockade on the enclave, blocking food, fuel and medical supplies, which are rapidly running out.

U.S. Secretary of State Antony Blinken announced Biden's planned visit at the end of hours of talks with Netanyahu, in which he said Netanyahu had agreed to develop a plan to get humanitarian aid to Gaza civilians. He gave no details.

"The president will hear from Israel what it needs to defend its people as we continue to work with Congress to meet those needs," Blinken said.

Biden would also "hear from Israel how it will conduct its 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", he added.

Washington is also trying to rally Arab states to help head off a wider regional war, after Iran pledged "preemptive action" from the "resistance front" of its allies which include the Hezbollah movement in Lebanon.

After visiting Israel, Biden is expected to travel to Jordan to meet King Abdullah, Egyptian President Abdel Fattah al-Sisi and Mahmoud Abbas, president of the Palestinian Authority which is a rival of Hamas and has limited self rule in the Israeli-occupied West Bank.