We are running out of chances to avoid all-out conflict in the Middle East

The large-scale air attacks carried out by Israel and Hezbollah in the early hours of Sunday morning mark the first serious escalation of the military conflict in the Middle East since the assassinations of a senior Hezbollah commander in Beirut and the Hamas leader in Tehran at the end of July. They threaten to unleash a new and still more dangerous stage of the war in and around Gaza, diminishing the fading hope that this 10-month-old conflict can be contained.

By any standards, this was a major exchange of firepower. According to Hezbollah, its action was the first stage in its long-awaited response to the killing of its commander. Israel, which launched its attacks first, with upwards of 100 aircraft, described its strikes as pre-emptive, after it had learned of an imminent Hezbollah assault, including on central Israel.

Israel’s chief fear is that Hezbollah rockets could breach its Iron Dome defence system and hit Tel Aviv, as was the case about a month ago when Houthi rebels in Yemen staged a successful missile strike on the capital. Any successful strike on central Israel would be guaranteed to propel the conflict to an entirely new level.

Hezbollah’s claim that this was the first stage of its revenge attack ensures that Israel and its allies will be standing by not only for whatever might be the next stage, but also for Iran’s response to the killing of Ismail Haniyeh in Tehran, as the result of a presumed, but not admitted, Israeli operation. The delay in any retaliation from Iran fed hopes in some quarters that concerted diplomatic efforts to dissuade Tehran from any counteraction might have had some effect.

They included a series of visits to the Middle East by the US secretary of state, Antony Blinken, a second trip to Israel by the UK foreign secretary, David Lammy, and a flurry of phone calls and joint statements that included the first conversation for three years between a UK prime minister and an Iranian president.

There were also a series of joint statements urging restraint. One of these came from the leaders of the UK, France and Germany. But there was also a wider statement, initiated by the US, with European support, pledging joint action to defend Israel in the event of an attack and unspecific consequences for Iran.

While Hezbollah – a known proxy of Iran – is largely a known quantity for Israel that it has been able to contain, Iran itself is another matter. Any direct military action by Tehran against Israel would transform the current conflict and risk a regional conflagration. While its response, in the form of multiple drone strikes, to a presumed Israeli attack on its consulate in Damascus, seems designed to have been little more than a gesture, it is very unlikely that this would apply another time.

Even if Iran can be persuaded to hold its fire for the moment, the latest exchanges between Hezbollah and Israel risk an irreversible spread of the conflict into southern Lebanon and possibly into Lebanon itself – which is why foreigners, including Britons, have been advised to leave. This, and the continuing fears of direct Iranian intervention, make it even more urgent to arrest the conflict where it stands.

And this, in turn, means addressing the failure, despite intensive international efforts, of Israel and Hamas to agree a ceasefire in Gaza coupled with the release of prisoners, including the surviving hostages from 7 October who remain in Hamas’ hands.

This deceptively simple objective has been thwarted by divisions and unrealistic expectations on both sides, with deal after proposed deal falling through. The latest sticking point is said to be Israel’s insistence on retaining a foothold in Gaza, while Hamas is demanding a complete Israeli withdrawal from the territory. The stakes for both sides are high, which is why any agreement is so difficult. For Hamas to give up all its hostages means giving up all remaining leverage on Israel. For Israel, a way back into Gaza constitutes a key security requirement, given what happened on 7 October.

Yet an immediate ceasefire and hostage release offers the only prospect of reducing, if not completely averting, the risk of escalation that has been so graphically demonstrated over the weekend. If there has been any hope to hang on to it has been the apparent preference of Iran – one of the key, but perhaps least predictable, players in the region – for restraint. Until now, this has included apparent efforts by Tehran to rein in Hezbollah. The events of early Sunday morning may serve as a warning that this preference for restraint could be nearing its end.

Another round of US diplomacy – given that the US is the only power with even limited ability to exert pressure on Israel – backed by a show of force to Iran may offer the only way forward. A second US aircraft carrier has just arrived in the region, and US Air Force general Charles Brown, who is chair of the US Joint Chiefs of Staff, has just started a circuit of Jordan, Egypt and Israel, adding an expressly military dimension to US diplomatic efforts.

It might be added that Joe Biden’s withdrawal from the US presidential contest could free the administration to take a more active diplomatic role without unduly affecting the Democratic Party’s fortunes in what promises to be a very close race. For several months there has been talk of Mr Biden himself eyeing a much wider settlement in the Middle East, in which an end to the Gaza war would be just a part. Now could be the time to revive this project, given the abject failure of other options and the relentlessly rising risks of a wider war.