Biden’s now cancelled summit in Jordan was aimed entirely at calming the rising fury of Arab leaders over the growing death toll in Gaza and the expected Israeli ground invasion of the territory.

Now the single biggest tragedy so far in Gaza — the loss of a reported 500 lives in an explosion at a hospital — has led Jordan to cancel the US president’s planned meeting with Palestinian Authority President Mahmoud Abbas, Egyptian President Abdel Fattah al-Sisi and Jordanian King Abdullah.

The cause of the explosion is contested; Hamas says it was an Israeli airstrike while Israel denies this and says it was a Hamas rocket which misfired.

It is likely that neither side will be able to prove its own claims, meaning that the political impact of the tragedy will still be hugely damaging to Israel because Palestinians across the Middle East will assume it was an Israeli rocket regardless of whether it was or was not.

That seems to have been the initial conclusion of PA chief Mr Abbas who withdrew from the meeting with the PA earlier accusing Israeli of genocide and ethnic cleansing in Gaza.

Egypt’s Mr al-Sisi has also expressed growing concern about Israel’s bombardment of Gaza saying previously that the operation had exceeded ‘the right of self-defence’ and had turned into ‘a collective punishment.’

And Jordan’s foreign minister — when announcing the postponement of the summit — said the war between Israel and Hamas was “pushing the region to the brink”.

This raises the stakes for Mr Biden’s meeting in Israel today with Israeli Prime Minister Benjamin Netanyahu. The visit — aimed at showing full US support for Israel in the conflict — is now likely to further antagonise Arab nations still raw from the hospital tragedy and the growing death toll in Gaza. Mr Biden is expected to call on Israel to do more to try to limit the civilian casualties and ease the humanitarian crisis in Gaza, both of which are impacting on its international reputation, notwithstanding the murderous Hamas attacks on Israel which triggered this conflict.

The stakes are high because the more that the Arab world unites against Israel, the greater the danger of the conflict spreading. Iran is poised - via its terror proxy Hezbollah on Israel’s northern border with a huge cache of missiles which it could choose to open a new front against Israel. It is playing a guessing game with the West, lobbing occasional rockets into Israel, while stopping short of an all out attack.

Violence in the occupied West Bank is also soaring and is at its worst level since 2006. The territory is a tinderbox.

The region really is on a knife-edge right now and this tragic incident — and the interpretation of it in the Arab world — only makes it more dangerous.