More than six months of Israel's military offensive in Gaza has turned the Palestinian territory into a "humanitarian hellscape", UN chief António Guterres said Thursday, also warning that one wrong move could see the Middle East devolve into wider war.
World powers have been watching nervously since Israel vowed to respond to Iran's retaliatory weekend attack on its arch enemy, with fears soaring that escalating tit-for-tat attacks could push the region towards broader conflict.
Israel's top ally and military supplier, the United States, and Britain unveiled sweeping sanctions against Iran's military drone programme as governments kept up calls for restraint from all sides.
In the latest in a series of threats between the two foes, Iranian Foreign Minister Hossein Amirabdollahian warned that Tehran would make Israel "regret" any attack on the Islamic republic.
While the world's attention has been focused on the Iran tensions, Israel has continued carrying out its war on besieged Gaza.
The Israeli army said it had bombed dozens of targets in the territory on Thursday, as Qatar said efforts to broker a truce had stalled.
"The Middle East is on a precipice," the UN's Guterres said.
"One miscalculation, one miscommunication, one mistake, could lead to the unthinkable – a full-scale regional conflict that would be devastating for all involved."
The UN chief again called for an immediate ceasefire in Gaza, calling for Israel to do more to allow aid into the territory.
"In Gaza, six-and-a-half months of Israeli military operations have created a humanitarian hellscape," Guterres told the UN Security Council.
His speech came hours before the Security Council is expected to vote on a Palestinian bid for full UN membership.
However the bid is expected to fail, as the veto-wielding US has voiced its opposition.
On the weekend, Iran carried out its first ever attack to directly target its regional foe but Israel, backed by its allies, intercepted most of the 300 missiles and drones, and suffered no deaths.
The attack was retaliation for a 1April Israeli strike that levelled Iran's consulate in Damascus and killed seven Revolutionary Guards, two of them generals.
Israeli Prime Minister Benjamin Netanyahu has stressed that Israel "reserves the right to protect itself" against Iran.
The US has made clear it won't join any Israeli attack on Iran, instead unveiling sanctions against people and entities involved in producing the drones deployed in the Iranian retaliation.
"We are holding Iran accountable," US President Joe Biden said, announcing the new measures after the European Union said it would also sanction Iran's drone programme.
Israel has yet to reveal how or when it will carry out its promised retaliation against Iran.
But US broadcaster ABC News, citing three unnamed Israeli sources, reported that Israel had "prepared for and then aborted retaliatory strikes against Iran on at least two nights this past week".
Among the range of possible responses considered by Israel were an attack on Iranian proxies in the region or a cyberattack, the sources told ABC.
On Thursday, a high-ranking Iranian general warned Israel against attacking Iran's nuclear sites.
If this did happen, then "the nuclear facilities of the regime will be targeted and operated upon with advanced weaponry", said Ahmad Haghtalab, the head of Iran's Nuclear Protection and Security Corps.
However, Tehran has also sought to calm tensions through indirect diplomatic channels with its other major adversary, the US.
Amirabdollahian said Iran had "tried to tell the United States clearly" that it is "not looking for the expansion of tension in the region".
Israel has faced growing global opposition to the relentless war that has reduced vast areas of Gaza to rubble, while its 2.4 million people have suffered under a crushing Israeli siege that has blocked most water, food, medicines, and other vital supplies.
Iran's attack on Israel "is succeeding in taking the focus, particularly the media spotlight, off of the Gaza famine and the Gaza war," Roxane Farmanfarmaian, a Middle East and North Africa specialist at Cambridge University, told AFP.
Israel's war on Gaza has killed at least 33,970 people in the strip, mostly women and children. according to the territory's health ministry.
A Hamas-led attack on 7 October resulted in the deaths of 1,170 people in southern Israel, mostly civilians, according to an AFP tally of Israeli official figures.
About 250 people were taken hostage. Israel estimates 129 remain in Gaza, including 34 who are presumed dead.
Gaza's civil defence said Thursday it had recovered 11 more bodies in the southern city of Khan Younis during the night.
Also bombed was the far-southern city of Rafah, where Israel told Palestinians in northern Gaza to move to earlier in the war – but has since vowed to invade on the ground.
An overnight Israeli strike killed at least 10 people where a displaced family was sheltering in Rafah, relatives and neighbours told AFP as they searched for the remains of victims.
"We retrieved the remains of children and women, finding arms and feet," said neighbour Abdeljabbar Al-Arja.
"This is horrifying, it's not normal," he said.
"The entire world is complicit."
The Al-Quds Brigades, the armed wing of Palestinian militant group Islamic Jihad, said it fired "a salvo of rockets" towards the Israeli cities of Ashkelon and Sderot, just over the Gaza border.
The Israeli army said sirens were heard Thursday evening in areas next to Gaza.