The US president is on his way just as Gaza reels from a hospital blast said to have killed hundreds.
Image source, EPA US President Joe Biden is due to arrive In Israel later on Wednesday to express his solidarity and to discuss war plans with its leaders.
But his visit has been hugely complicated by a blast at a hospital in Gaza which is feared to have killed hundreds of Palestinians.
The president sent his “deepest condolences” to the victims.
A visit to Jordan to meet Arab leaders was cancelled amid international outrage over the deaths in Gaza.
Mr Biden will meet Israeli Prime Minister Netanyahu in a “very small restricted bilateral meeting” as well as the Israeli war cabinet, US National Security Council spokesman John Kirby said.
The president will also meet first responders to the attack by the Hamas Palestinian militant group on Israel which left 1,300 Israelis dead on 7 October, and some of those who lost loved ones or whose family members are being held hostage, Mr Kirby said.
Israel has asked the US for $10 billion (£8.2 billion) in emergency military aid, the BBC’s US partner CBS News reports, quoting what it calls sources familiar with the request.
The Hamas-led authorities in Gaza say 500 people died in the explosion at the Al Ahli hospital, which one doctor called “a massacre”.
Hamas blamed Israel, calling it a “war crime”. A spokesperson for Palestinian Authority President Mahmoud Abbas, who is based in the occupied West Bank, accused Israel of a “heinous crime”.
But Israel said the blast had been caused by rockets misfired by another group, Palestinian Islamic Jihad.
“Our intelligence is reporting to us that apparently there was a rocket launched by Islamic Jihad…” Mark Regev, a spokesman for Mr Netanyahu, told BBC radio 4.
“And that their rocket was fired into Israel but dropped short and landed on the hospital, causing the destruction it did.”
The BBC is working to verify what caused the blast.
This video can not be played
To play this video you need to enable JavaScript in your browser.
Mr Kirby said the president would be “asking tough questions” of Israeli officials. “He’ll be asking them as a friend, as a true friend of Israel, but he will be asking some questions of them.”
He added that 31 Americans had been killed in the Hamas attacks, while 13 in Israel remained unaccounted for.
At least 3,000 people have been killed in Israel’s bombardment of Gaza, according to health officials.
More on Israel-Gaza war
- Follow live: Latest updates
- Explained: What’s going on in Gaza and Israel, and why now?
- History behind the story: The Israel-Palestinian conflict
- Hamas’s attack on Israel: Who are the hostages?
- Inside Gaza: The families who won’t evacuate