Lebanon holds its breath for a possible third day of explosions as Hezbollah leader prepares to address the nation amid fears Israeli pager bombs will spark all-out war and Iran vows revenge

Lebanon is reeling after thousands of pagers and walkie-talkies belonging to Hezbollah fighters exploded during two days of carnage, leaving thousands with horrific injuries, dozens dead, and many now terrified of a repeat attack.

Israel has been accused of orchestrating the blasts, and while it has not claimed responsibility, Hezbollah and its backers Iran have condemned their arch-foe for carrying out 'mass murder' and have vowed to exact revenge.

The chief of Hezbollah, Hassan Nasrallah, is set to make an address this afternoon, with Lebanese civilians holding their breath over how the hardline militia will retaliate and how Israel will respond in turn.

In a sign that a major escalation is imminent, Israel's defence minister Yoav Gallant last night declared a 'new phase' of the war had begun, after nearly a year of cross-border fighting with Hezbollah.

Israel has been moving more troops and tanks to its northern border since the pager blasts began, ratcheting up fears of a regional conflagration as commentators and officials have warned that the Middle East is on the brink of all-out war.

Less than 48 hours after the first surprise blasts saw Hezbollah fighters' pagers detonate across Beirut, southern Lebanon and in Syria, many are now waiting with bated breath to see if a third wave of attacks will follow today.

Fearing that yet more devices could be booby-trapped, panicked Hezbollah fighters have torn the batteries from their walkie-talkies and thrown them into open spaces.

Civilians have spoken of their terror that their mobile phones and other home devices could effectively be turned into bombs, with reports that many are removing their batteries and Lebanese SIM cards.

'We don't know if we can stay next to our laptops, our phones. Everything seems like a danger at this point and no one knows what to do,' one local told the BBC.

Exploding walkie-talkies killed 20 and injured at least 450 people on Wednesday, including mourners at a funeral for three Hezbollah fighters and a child killed in the blasts the previous day, according to Lebanon's health ministry.

On Tuesday, exploding pagers killed 12, including two children, and left almost 3,000 injured.

Tehran last night threatened that it will 'follow up' after its ambassador to Beirut was confirmed to be among the injured in the attacks.

The Islamic Republic's envoy to the UN warned in a letter that it 'reserves its rights under international law to take required measures deemed necessary to respond to such a heinous crime and violation.' 

In news which is bound to further fuel tensions, it was also revealed today that Iran allegedly recruited an Israeli civilian to assassinate prime minister Benjamin Netanyahu, with the individual arrested last month.

As bellicose rhetoric is ramping up on both sides, the United Nations and governments around the world have called for calm, with France urging 'maximum restraint' and Britain calling for 'de-escalation'.

Lebanon's ambassador to the UK, Rami Mortada, warned this morning that the Middle East is the closest it has been in 50 years to a regional war that would 'spare no one'.

Speaking on Sky News, he said that Israeli 'war crimes' have put the region on 'the brink of an all-out war'.

He blamed Benjamin Netanyahu, saying the Israeli prime minister was holding the 'whole region hostage' and had 'put his country at a continual state of war' in order to keep his grip on power.

Israel's defence minister Gallant, a former general, said yesterday of his country's war strategy that 'the center of gravity is moving north. We are diverting forces, resources, and energy toward the north.'

In an expansion of Israel's official war goals on Tuesday, Netanyahu announced that his forces would now aim to halt Hezbollah's attacks in the north to allow tens of thousands of residents to return to their homes along the border.

He reiterated this in a brief video statement last night, saying: 'I've already said we will return [the displaced] residents of the north safely to their homes, and that is exactly what we will do.'

Hezbollah said 20 of its members had been killed in yesterday's attacks, vowing revenge against Israel who it said was 'fully responsible for this criminal aggression'.

At 5.00 pm (1400 GMT) today, Hezbollah leader Hassan Nasrallah will give a previously unscheduled televised speech to 'address the latest developments'.

It will be watched closely by both his supporters and his enemies for any signals of what shape a response might take.

Speaking to Israel's public radio, former deputy Mossad chief Ram Ben Barak warned that even though Hezbollah had been 'infiltrated', it could still launch an attack in a short space of time.

'We need to get rid of the euphoria and prepare for a major event in the north,' he reportedly said.

Meanwhile a leading war crimes barrister has warned that the device explosions could amount to a 'criminal act'.

Sir Geoffrey Nice, who led the prosecution of Slobodan Milosevic, said that the distribution of the devices 'without any certain knowledge of where they would be at the time of activation', could have meant they were being used by 'non-combatants'.

'Non-combatants are not entitled to be treated by... random bombs in the way these have happened,' he told BBC Radio 4.

'The second possibility is that this is simply an attack on civilians, and it's conceptually pretty much the same as Hamas unguided missiles into non-military parts of Israel.

'And then thirdly... is the question of proportionality, even if there was any justification in law for what it's assumed Israel has been doing.'

Now scrutiny is turning to the origins of the detonated devices, all of which were bought by Hezbollah around five months ago out of fear that Israel could hack smartphones and other communication devices.

A Taiwanese pager maker denied that it had produced the pager devices which exploded in the audacious attack.

Gold Apollo said the devices were made by under licence by a company called BAC, based in Hungary's capital Budapest.

Meanwhile Japanese firm Icom said Thursday that it had stopped producing the model of radios reportedly used in recent blasts in Lebanon around 10 years ago.

'The IC-V82 is a handheld radio that was produced and exported, including to the Middle East, from 2004 to October 2014. It was discontinued about 10 years ago, and since then, it has not been shipped from our company,' Icom said in a statement.

'The production of the batteries needed to operate the main unit has also been discontinued, and a hologram seal to distinguish counterfeit products was not attached, so it is not possible to confirm whether the product shipped from our company,' it said.

It added that products for overseas markets are sold exclusively through its authorized distributors, and that its export programme is based on Japanese security trade control regulations.