Carine Torbey
Reporting from Beirut

Image source, EPA-EFE/REX/Shutterstock

Hours after the mass attack, ambulances were still rushing to hospitals which were overwhelmed with the number of casualties.

Outside, relatives of the injured were gathering in the hope of receiving any updates.

The hospital where we went was closing its main gate and limiting the number of people getting in.

"It's very sensitive and some scenes are horrific," one hospital staff member told me. He added that most injuries are on the level of the waist, the face, the eyes and the hands.

I was told:

Tonight, the whole country is in a state of disbelief and shock, with people unable to get their heads around what really happened.

It is unprecedented in scale and nature and extremely hard to fathom even for a country used to unfathomable events.

Videos posted online show injured taken to hospitalpublished at 20:12 British Summer Time 17 September

20:12 BST 17 September

By Richard Irvine-Brown

Image source, Telegram

Among the videos BBC Verify has been looking at this afternoon are several showing the aftermath of the explosions.

Two videos show the scene of ambulances and crowds gathering at the entrance to the hospital in Tebnin, a town 75km (46 miles) south of Beirut.

Meanwhile, in the capital Beirut, a video from inside Bahman Hospital shows the injured and dead in corridors and doorways, with doctors squeezing past to treat them and other medics calling for help, while more patients arrive on stretchers.

In the two-minute tour through the hospital's ground floor and western courtyard, we count at least 28 patients either being treated, carried in, or already bound with bandages.

Another video, taken on Waked Street, 320m north of the hospital shows two injured men being helped by members of the public. One, bleeding heavily from his hand and possibly his head is helped toward a car, while another is lifted off the road by three men.

Hezbollah considers this an escalation - what comes next is unclearpublished at 20:03 British Summer Time 17 September

20:03 BST 17 September

Daniel De Simone
Reporting from Jerusalem

Some in Israel have been arguing for the need of a military operation in southern Lebanon to create a buffer zone to tackle the threat from Hezbollah.

Others have counselled against such a step given the potential impact of a bigger war. Hezbollah, which is backed by Iran, has been regarded by many as better trained and equipped than Hamas.

Yesterday, US Defence Secretary Lloyd Austin warned of the devastating consequences of further escalation.

From Hezbollah’s statement today, the group considers an escalation has now taken place. What happens next is unclear.

Attack comes after Israel's previous warnings about its border with Lebanonpublished at 20:03 British Summer Time 17 September

20:03 BST 17 September

Daniel De Simone
Reporting from Jerusalem

The explosions today came only hours after Israel's security cabinet made the safe return of residents to the north of the country an official war goal – the only one of four overall goals relating to the north.

Israel has repeatedly warned it could launch a military operation to drive Hezbollah away from the border, and yesterday the Israeli Defence Minister Yoav Gallant warned that, failing a political solution, "military action" would be the only option to ensure the return of Israeli citizens to the north.

Since the Hamas attack on Israel on 7 October last year, and Israel’s continuing assault on Hamas in Gaza, there has also been a significant conflict with Hezbollah.

The militia has been sending rockets and drones into Israel, with the Israeli air-force conducting frequent raids against the group's positions and members. Thousands of cross-border attacks have taken place.

The UN says the conflict has forced more than 90,000 people in Lebanon from their homes. In Israel, officials say 60,000 civilians have had to abandon where they live.

Frances Mao
Live reporter

Based on the few details we know so far, several analysts are also suggesting the attack came about from weaponised pagers being supplied.

Hezbollah has used pagers instead of mobile phones since earlier this year when the Israelis used them as tracking tools to find and kill commanders. They've been in use for a while now. But this could have resulted from a new batch being supplied.

"This was a new shipment," says Prof Janane El-Khoury from Lebanese University. "Who allowed this new shipment to come to Lebanon to be distributed to Hezbollah members?"

Former CIA Middle East analyst Emily Harding also says it looks like a supply chain attack. "Perhaps Hezbollah did a refresh of their pagers, and the new ones were altered. Then the trigger must have been some kind of signal."

She said knowing where the victims were, and if the explosions happened all at the same time, would help paint a clearer picture.

Among the nine people killed is a girl, as we reported earlier.

The girl is the daughter of a Hezbollah member and died in east Lebanon's Bekaa Valley when his pager exploded, AFP news agency reports.

Nearly 3,000 are injured, according to Lebanon’s health minister Firass Abiad.

The US responds with apparent surprise to the pager explosions.

State Department spokesperson Matthew Miller says: "The US was not involved in it, the US was not aware of this incident in advance and, at this point, we’re gathering information."

He adds that the US does not know who is responsible.

Earlier reports indicate that both Hezbollah and Lebanese officials blame Israel, which has yet to comment.

Miller also addresses the apparent injury of Iran's ambassador in the explosion. "We would urge Iran not to take advantage of any incident to try to add further instability and to further increase tensions in the region," he says.

Image source, EPA

In short, it's a politically-influential Shia Muslim organisation which controls the most powerful armed force in Lebanon.

It was established in the early 1980s by the region's most dominant Shia power, Iran, to oppose Israel. At the time, Israel's forces had occupied southern Lebanon during the country's civil war.

Hezbollah has participated in national elections since 1992 and has become a major political presence.

Its armed wing has carried out deadly attacks on Israeli and US forces in Lebanon. When Israeli troops withdrew from Lebanon in 2000, Hezbollah took credit for pushing them out.

Since then, Hezbollah has maintained thousands of fighters and a huge missile arsenal in southern Lebanon. It continues to oppose Israel's presence in disputed border areas.

The group is designated a terrorist organisation by Western states, Israel and Gulf Arab countries.

In 2006, a Hezbollah cross-border raid triggered a full-blown war between the group and Israel, with Israeli troops invading southern Lebanon - but Hezbollah survived the conflict.

Daniel De Simone
Reporting from Jerusalem

An update now on the number of people killed in Lebanon.

Dr Firass Abiad, the country's minister of public health, says nine have died and thousands more are injured after pagers being used by Hezbollah exploded in southern Beirut and several other areas of the country.

We're hearing that people in Syria, which borders Lebanon, have also been injured by the exploding pagers.

"Fourteen people whose nationalities are unknown have been wounded in Damascus and its countryside after pagers used by Hezbollah exploded," the Syrian Observatory for Human Rights - a UK-based monitoring group - says.

The is in addition to the eight who've so far been announced dead and almost 3,000 injured in Lebanon.

We've just heard from the Israel Defense Forces (IDF), who say in a statement they've held a situational assessment this evening.

"At this time there is no change to the Home Front Command defensive guidelines," says an IDF spokesperson. These are the directives issued by the Israeli military for civilians to follow in order to keep themselves safe in the event of an attack.

"The public are asked to remain alert and vigilant, and any change in policy will be updated immediately," the statement adds.

The IDF are still yet to comment on the pager explosions.

• As a reminder: Both Hezbollah and Lebanese officials have, in the past couple of hours, blamed Israel for the pager attacks.

Ben Hatton
Live reporter

Image source, EPA

Pagers used by Hezbollah have exploded simultaneously, with almost 3,000 people reported to have been injured. The Iranian-backed Lebanese armed group, which is banned as a terrorist organisation in the UK, US and other countries, says an investigation into the cause is under way.

Here's what we know so far:

Casualties:Hezbollah says two of its fighters and a young girl have been killed. The Lebanese health ministry say eight people have been killed and at least 2,750 injured. Iran’s ambassador to Lebanon - Mojtaba Amani - is reportedly among the injured.

Hezbollah blames Israel: A statement from the group says Israel is "fully responsible for this criminal aggression that also targeted civilians". It says "this treacherous and criminal enemy will certainly receive its just punishment".

Lebanese officials also blame Israel: That's according to reports from local media in Lebanon. The country's information minister Ziad Makary has condemned the pager blasts as "Israeli aggression" according to Lebanon's Al-Manar TV broadcaster.

Israel is yet to comment: We've not yet had a statement from the Israeli military, who have been engaged in cross-border fire with Hezbollah for months. The explosions come hours after Israel made the return of residents displaced by Hezbollah attacks one of its war goals.

Shop CCTV appears to show pager explosionpublished at 18:16 British Summer Time 17 September

18:16 BST 17 September

By Richard Irvine-Brown

Warning: This post contains distressing scenes

We have been looking into dozens of videos from this afternoon.

Some of those are difficult to verify, including this one inside a shop. It shows a small explosion which appears to injure a single person.

While we are yet to establish where this was filmed, we have reverse-searched four frames from it and know Google had not cached a copy as of 16:30 BST today.

This means it is very likely it was first uploaded in the early afternoon.

The video appears to be CCTV and even has today's date and a timestamp of 15:30 local time (13:30 BST), matching reports of when the explosions occurred.

Frances Mao
Live reporter

I've been speaking to several Middle East security analysts who say the nature and scale of the attack on Hezbollah appears unprecedented.

"It’s extraordinary. Hezbollah prides itself on its strict security measures, honed over decades of going head to head with Israel," Emily Harding, a former senior CIA analyst who was also the Iran director at the National Security Council tells me.

She and others say this is a critical breach of Hezbollah's security.

"A breach of this magnitude is not only physically harmful, but will also make them question their entire security apparatus," says Harding, currently a deputy director at the US-based Center for Strategic and International Studies think tank.

"I would expect to see them conduct an intensive internal investigation that will distract them from a potential fight with Israel."

Lina Khatib, from the UK-based Chatham House, says the attack "underlines how deeply Israel has infiltrated Hezbollah's communications network".

"Many Hezbollah operatives switched to using pagers after mobile phones belonging to Hezbollah members were compromised by Israeli hacking.

"The scale of the latest attack is deeply humiliating for Hezbollah, showing how vulnerable Hezbollah's security is in the face of sophisticated Israeli military technology," she adds.

Joe Tidy
Cyber correspondent

Supply chain attacks are a growing concern in the cyber security world with many high-profile hacks recently caused by hackers gaining access to products whilst they are in development.

But these attacks are normally contained to software.

Hardware supply chain attacks are far rarer as they involve getting hands on to the device.

If this was indeed a supply chain attack it would have involved a huge operation to open the pagers in a factory like setting and secretly tamper with them in some way.

As security expert Dmitri Alperovitch said on X this would make the operation "perhaps one of the most extensive physical supply chain attacks in history".

Frank Gardner
Security correspondent

The mass sabotage of such a large number of Lebanese pagers required both timely intelligence and technical capability.

Since the start of the Gaza conflict last year, Hezbollah had warned its members not to use mobile phones for fear they could be tampered with by Israeli intelligence agents.

Back in 1996, Israel’s Shin Bet agency assassinated a Hamas bombmaker with explosives in his phone.

Instead, Hezbollah were using pagers to communicate, with a new batch delivered recently.

Somebody - and Hezbollah are in no doubt that Israel was behind this - was able to secretly insert themselves into the supply chain for those pagers.

A former British Army munitions expert, who asked not to be named, told the BBC the devices would have likely been packed with between 10 to 20 grams each of military-grade high explosive, hidden inside a fake electronic component.

This, said the expert, would have been armed by a signal, something called an alphanumeric text message.

Once armed, the next person to use the device would have triggered the explosive. Less than 1% of the exploding pagers have so far proved fatal, but with hundreds seriously injured this is a major psychological blow to Hezbollah.

There are reports coming through of Lebanese officials also attributing the explosions to Israel.

The country's information minister Ziad Makary has condemned the pager blasts as "Israeli aggression" according to Lebanon's Al-Manar TV broadcaster.

Makary says he has also been in touch with the United Nations to “hold the culprit accountable", Al-Manar also reports.

Israel is still yet to comment on the attacks.

Hezbollah has said two of its fighters and an eight-year-old girl have been killed. The Lebanese health ministry say eight people have been killed and at least 2,750 injured.

Iran’s ambassador to Lebanon - Mojtaba Amani - is reportedly among the injured. Iranian State TV reports his wounds are "superficial" and that he is "conscious and in no danger".

Hezbollah's chief, Hassan Nasrallah, was not harmed in the blasts, according to Reuters which quotes a senior Hezbollah source.

Unverified CCTV footage circulating on social media appear to show the blasts, including one video of what appears to be an explosion in a man’s trouser pocket as he stood at a shop till.

Pictures from Beirut show chaos on the city's streets, as wounded people are taken to hospital.

Image source, Reuters

Image source, Reuters

Image source, Reuters

More from Hezbollah's statement now, which says it holds Israel "fully responsible for this criminal aggression that also targeted civilians".

"This treacherous and criminal enemy will certainly receive its just punishment for this sinful aggression, whether it expects it or not," it adds.

The Lebanese armed group also reiterates its "support and backing for the valiant Palestinian resistance".

Israel has yet to comment on the explosions.