Iran may hit back at British and US targets in Middle East after Israel killing of Hezbollah chief - as region risks being plunged into wider war, experts warn

The death of Hassan Nasrallah in Lebanon will come as a devastating blow to Hezbollah after thirty years under his leadership, prompting urgent reactions from allies and potentially threatening Western interests in the Middle East, experts warn.

Israel's military announced that Hezbollah's secretary-general had been killed this morning, hours after pounding Beirut with heavy strikes through Friday afternoon.

Hezbollah confirmed the reports this afternoon, and the region will be pressed to move quickly; officials briefed by Tehran told Reuters that Iran's supreme leader had already been moved to a secure location, while Israel went on high alert anticipating a response.

Israel's allies and adversaries will now be looking very closely at what happens next. Much of Hezbollah's central leadership has been 'decapitated' by Israeli attacks in recent days, experts told MailOnline, but Israel will feel urged to continue its incursion.

Still, Hezbollah remains backed by Iran, which has vowed to stand up for its proxy groups in the Middle East as perceived Israeli aggression continues unabated. Iran will be 'embarrassed' by Israel's operations in Lebanon and 'try to show the region that they are still strong', risking future attacks and greater destabilisation.

And with a power vacuum emerging in Lebanon, analysts warn Hezbollah could fall back on the radical militarisation of decades gone by if the country is unable to reconstitute and reform. Here, domestic and foreign actors find greater room to manouevre - and Israel's allies in Britain and the United States may too be swept up in a widening conflict.

Hezbollah has been dubbed a 'state within a state in Lebanon', with the group long entrenched in civil affairs, filling in for a government blighted by corruption and dire economic woes.

Hassan Nasrallah oversaw the transformation of the organisation from a militant group forged in the Lebanese Civil War and the 1982 Israeli invasion into a significant political and military player in the region. 

The reported 'beheading' of the Hezbollah will be marked down as a major victory for Israel, which has stepped up its attacks into Lebanon in recent days after nearly a year of missile exchanges across the border.

But the killing of a figure with such strategic and 'immense symbolic value' could plunge the region into further trouble, with Hezbollah and its backers likely pressed to deliver an urgent response.

Philip Ingram MBE, a former British military intelligence, counterintelligence, and security officer, told MailOnline that Iran will be 'further embarrassed' by Israel's reported successes against Hezbollah.

'The Iranian response would be one that we have to watch very closely,' he said.

'They will want to come out and try and show to the region that they are still strong and therefore I suspect we will see an increased number of attacks focused not just on Israeli interests and the possibility of an attack from Iran against Israel itself... but then attacks against US, UK and allied interests across the Middle East and potentially across the world.'

Col. Ingram said this could materialise as 'terrorist attacks against US bases in Syria, Jordan and Iraq' or the 'further encouragement of attacks by the Houthis against commercial shipping in the Red Sea'.

Britain and the United States continue to operate from bases across the Middle East, and maintain small presences in countries stretching from Turkey to Oman.

Col. Ingram said that 'these aren't going to be formal military attacks. They may fire rockets into Israel', but this would likely be a limited strike as 'they won't want Israel directly attacking Iran'.

'But we are very quickly running up a lot of escalation - and that's a very dangerous thing to do.' 

Dr Andreas Krieg, Assistant Professor of Defence Studies at King's College London, told MailOnline: 'What's likely going to happen here is that Iran will have to do something because the red line was crossed. 

'They might give permission to use more ballistic missiles, more to attack more strategic targets in Israel, knowing that then the IDF will likely move into Lebanon.

'Obviously Hezbollah will have to respond. Iran will have to respond and, if they do, I think they will have to respond in kind, which means they will have to hit strategic targets.

'They need to get out of their modus operandi that they have been in for the last 12 months, which was below the threshold of war. This all out war is happening. This is all out war for Lebanon.'

'A big concern across the region is that this tit-for-tat has got out of control and all thresholds have been crossed. All lines have been crossed and so we are in this all out war situation now, and that's going to be very difficult to rein in.'

Such a 'seismic event' for regional politics is likely to have a 'major impact' on the 'Axis of Resistance beyond Hezbollah', forcing escalation with Israel, while trying to avoid overspilling into the Gulf.

Dr Burcu Ozcelik, Senior Research Fellow for Middle East Security at the Royal United Services Institute defence and security think tank (RUSI), added: 'Hezbollah was Iran's most strategically significant asset and main deterrent against Israel. 

'This has been severely degraded now and how Iran chooses to respond will be highly consequential as the conflict evolves.'

Iran's Supreme Leader Ayatollah Khamenei called on Muslims on Saturday to 'stand by the people of Lebanon and the proud Hezbollah with whatever means they have and assist them in confronting the ... wicked regime (of Israel)'.

He said in a statement: 'The fate of this region will be determined by the forces of resistance, with Hezbollah at the forefront', state media reported.

Foreign Minister Nasser Kanani added on Twitter/X: 'The glorious path of the leader of the resistance, Hassan Nasrallah, will continue and his sacred goal will be realised in the liberation of Quds (Jerusalem), God willing.' 

In Lebanon, the question now turns to stability. Without a clear successor for Nasrallah, concerns mount that a more radical leader could replace him, reverting the group to the most 'belligerent' politics of decades gone by.

'Hezbollah and Iran have been quite rational in terms of how they have been acting, but now it's time to escalate for them as well if they want to survive,' assessed Dr Krieg.

'I suspect there will be more radical voices coming in... I think we're moving into a space of possibly more radical elements who, like Nasrallah in the 1980s and 90s, are far more militaristic and belligerent.

'I don't think Israel has done itself a favour because what will come next within Hezbollah will likely be worse, less restrained, and will most likely not get them the sort of peace they want in the north.' 

'Research shows that every time Israel does kill a leader ... over the last 40 years or so, in any of the organisations against which Israel has fought, it will lead to a more radical individual taking that place, so it has been a self-defeating strategy, this sort of strategy of whack-a-mole.

'So I don't think it will end Hezbollah as an organisation. Certainly, the narrative of resistance, particularly in the south of Lebanon, is still very strong.' 

'Nasrallah has shaped the organisation in his own image ... and so taking him out open a big question about who's going to succeed, and Israel has killed quite a lot of the operational leadership as well.'  

But Hezbollah as a network is 'extremely resilient' and 'will continue to function', he said.

Dr Ozcelik added: 'The deep entanglement between Lebanon and Hezbollah is now being tested and interrogated by those who have long opposed Hezbollah. 

'Amid the uncertainty and fear in Lebanon, this may be an opportunity for Lebanon to reconstitute its internal dynamics. 

'But it will not be easy, and Hezbollah will not vanish overnight as a significant actor inside Lebanon and the region despite the pummelling it has endured.'

Outside of Lebanon, analysts believe others may now also try to 'exploit the opportunity to seize power' at the expense of Hezbollah's influence. 

'Vladimir Putin is eagerly watching the outcome of this very closely indeed,' Col. Ingram added, as the focus on the 'regional perspective of the Middle East' detracts attention from the war in Ukraine.

'Combined with what's going on inside Ukraine, stimulating the start of a global conflict of some description - that potential has just increased.'

Reuters cited security sources this week claiming Iran was staging secret talks to send Russian anti-ship missiles to the Houthi rebels in Yemen, sparking fears Putin could be deliberately 'stoking conflict' in the region.

Edmund Fitton-Brown, Senior Advisor to the Counter Extremism Project and former Ambassador of the UK to Yemen, told MailOnline: 'Any successful upgrade of Houthi capabilities would also likely draw a kinetic Israeli response.'

He added that such a deal could 'draw clearer lines of alliances' between an axis of Russia and Iran against the West.

Despite calls from its allies to de-escalate and leave Lebanon, Israel seemed intent on continuing its press into Lebanon.

This morning the IDF announced it was mobilising three reserve battalions to bolster the defences of its central command.

Israel's Chief of Staff, Lt. Gen. Herzi Halevi, said Saturday that the elimination of Nasrallah was 'not the end of our toolbox.' 

He said that the strike targeting Hezbollah leadership was the result of a long period of preparation and they would 'reach' anyone who threatens Israel. He added that the army is 'at full readiness in all of our fronts'.

'There's still a way to go. Hezbollah still has rockets and missiles and has the capability of shooting many of them simultaneously,' military spokesman Lieutenant Colonel Nadav Shoshani added to an online press briefing.

And experts this morning said that Israel appears to be 'softening' Hezbollah ahead of a ground invasion. 

From its perspective, 'Israel has to continue,' warned Col. Ingram. 'It's started the super tanker moving. You can't stop it.

'If you do stop it, it's going to take a lot more effort to restart it again. It's going to result in a lot more casualties and not just with the Israeli military.

'Having to restart it again, you have to go in more violently. And therefore there's going to be greater civilian casualties. Israel has to go forward, but they will have to set themselves limits.

'They can't afford to go and try and capture Beirut, capture Lebanon because that's going too far. I suspect they will go into the demilitarised zone and demilitarise it as much as they possibly can.

'And all this means that Iran ... will be further embarrassed.'

Hezbollah was founded in the milieu of the Israeli invasion of Lebanon in 1982, with forces pushing all the way to Beirut in a bid to oust the Palestine Liberation Organization.

With backing from Iran, Lebanese groups managed to push Israel back. Hezbollah grew with backing from Iran into the force it is today, and cultivated some respect from people who still remember the Israeli invasion.

Radicalised by the events, Hezbollah sought the obliteration of Israel as a founding aim. It also sought to remove US and French peacekeepers from the region.

Nasrallah was credited with Hezbollah's success in pushing Israel out of southern Lebanon with the 2000 withdrawal, and holding it to a stalemate in the 34-day war in 2006.

The killing of Nasrallah shows 'how determined and also how reckless the Israelis are' in their willingness to achieve their objectives, said Dr Krieg, 'defying international law, defying conventions of warfare' in the killing of civilians in Gaza and Lebanon.

'I think it's an enormous source of strength now, for Israel, as it shows how far they are willing to go with near total destruction.'

The death of Hezbollah leader Hassan Nasrallah is one of the most significant developments in regional politics in recent years.

Israeli operations in recent days have forced a staggering transformation of Hezbollah, with many of Nasrallah's lieutenants no longer placed to step up.

In this vacuum, domestic and foreign powers stand to gain new influence over Lebanon, potentially at the expense of the civilian population and government.

And as Hezbollah's allies try to forge a proportionate response under a new state of play, onlookers will fear the conflict could erupt into a wider war.

What happens in the coming hours will have real implications for the lives of millions of people throughout the Middle East and beyond.