US President Joe Biden has arrived in Israel to express his solidarity and discuss war plans with its leaders.
He landed in Tel Aviv on Wednesday and was greeted warmly by Israeli Prime Minister Benjamin Netanyahu.
But the high-stakes visit has been overshadowed by a blast at a crowded Gaza hospital in which hundreds are feared to have died.
The blast, which Palestinian and Israeli officials have blamed on each other, has further stoked tensions.
In a statement issued from Air Force One, Mr. Biden said the US mourned “the patients, medical staff and other innocents killed or wounded in this tragedy” but he did not attribute blame.
Mr Biden had planned to travel from Israel to Jordan to meet Arab leaders, but that leg of the trip was cancelled after the deaths in Gaza on Tuesday inflamed tensions and sparked protests.
Jordan cancelled the meeting and condemned what it called “a great calamity and a heinous war crime”. The White House, meanwhile, said the decision had been “made in a mutual way” and Mr Biden would call the leaders of the Palestinian Authority and Egypt on his return flight to the US.
Mr Biden and Mr Netanyahu held a joint news conference shortly after he arrived, and the US president is expected to meet the Israeli war cabinet later on Wednesday.
He will ask “tough questions” to better understand Israel’s war aims and objectives in Gaza, US National Security Council spokesman John Kirby said.
“He’ll be asking some tough questions but he’ll be asking them as a friend,” Mr Kirby told reporters, adding that the US would stress the need for humanitarian aid to enter Gaza and the obligation to avoid civilian casualties.
Mr Biden will also meet emergency workers who responded to the unprecedented attack by the Hamas Palestinian militant group which left 1,300 Israelis dead on 7 October. Hamas gunmen breached the border and infiltrated Israeli communities close to Gaza.
He will also meet some of those who lost loved ones or whose family members are being held hostage, officials said.
At least 3,000 people have been killed in retaliatory Israeli strikes on Gaza, according to health officials.
Israel has asked the US for $10bn (ÂŁ8.2bn) in emergency military aid following the attack, the BBC’s US partner CBS News reported, quoting what it called sources familiar with the request.
The Hamas-led authorities in Gaza say 500 people died in the explosion at the Al Ahli hospital on Tuesday, 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 was 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 the BBC.
“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.