Nine people were killed and 2,800 were wounded in Lebanon including Iran's ambassador when pagers used by Hezbollah members detonated throughout the country on Tuesday according to the Lebanese health ministry, in a likely Israeli attack.
Iran’s ambassador to Lebanon was wounded and remained in hospital with non-life-threatening injuries, Iran’s state-run news outlets said.
Hezbollah, which has been locked in escalating cross-border combat with its southern neighbour for almost a year, blamed Israel for the attack and vowed retaliation.
"We hold the Israeli enemy fully responsible for this criminal aggression ... This treacherous and criminal enemy will certainly receive its just punishment for this sinful aggression", the Iranian-backed group said in a statement.
Israel has not yet commented on any role in the incident but has repeatedly assassinated adversaries in combat zones and beyond in the past.
It was not immediately clear how the pagers were detonated and the apparent attack comes after Hezbollah leader Hassan Nasrallah urged his fighters last year to ditch smart phones and adopt less traceable means of communicating.
Unverified surveillance camera videos posted online by Lebanese users appeared to show detonations felling a man at an outdoor fruit market and in a supermarket checkout aisle.
Other footage showed what appeared to be a hospital ward crowded with wounded men and also the inside of a bedroom with a mirror and cupboard torn apart by an apparent blast.
Fourteen people were also wounded in the Syrian capital Damascus and its outskirts in blasts around the same time, the Syrian Observatory for Human Rights reported.
Hezbollah fighters have been a party to Syria's civil war for over a decade.
The attack ratchets up the conflict between Hezbollah and Israel that has rumbled since the group’s Palestinian allies Hamas attacked Israel on October 7.
Israel’s security cabinet on Monday upgraded the country’s war aims to include securing its Northern border, where Israeli and Lebanese communities have been evacuated for almost a year.
The Israeli military announced on Monday that it had foiled a suspected assassination attempt on an unnamed senior security official.
The explosive device found in Israel was equipped with a remote activation mechanism, with a camera and cellular technology, that enabled it to be activated by Hezbollah from Lebanon, it said in a statement.
The Israeli military said that the device was similar to the Claymore explosive used by Hezbollah in September last year, in Yarkon Park in Tel Aviv, which was intended to target a senior Israeli official.