Lebanese Shia group Hezbollah said it launched a drone attack against an Israeli military training base south of the city of Haifa on Sunday evening killed four and wounded 61 Israelis, in the largest blow for the Israeli army since fighting broke out over a year ago.
The Iran-backed group launched "a squadron of attack drones at a training camp... in Binyamina, south of Haifa," it said, in "response to Zionist attacks" including Israeli air strikes in the central Beirut neighbourhoods of Basta and Nweiri that killed 22 people on Thursday.
The Israeli army said on Sunday that four people were killed in the attack which hit the base of the Golani Brigade. Israel's ambulance service said 61 were being treated for injuries in nearby hospitals with seven people critically wounded.
The Hezbollah drone strike is the bloodiest on Israeli soil since fighting began over a year ago. The Golani Unit, one of the army's top tier, that was targeted by Hezbollah has been deployed in southern Lebanon over the past few weeks, having spent time fighting in Gaza.
Israeli media reported that three drones entered Israeli air space and one of them struck the base in Binyamina, south of Haifa and north of Tel Aviv. It comes as tensions remain high ahead of an anticipated Israeli response to Iran's missile attack ten days ago.
Reports suggested that the Israeli military have put an embargo on further reporting of the attack on its military base due to security concerns within the country. The military has taken similar action in the past.
An Israeli volunteer rescue service on Sunday said more than 60 people were wounded with four people critically.
"With the help of United Hatzalah ambulance teams, we provided assistance to over 60 wounded people with varying degrees of injuries - critical, serious, moderate and mild," the rescue service United Hatzalah said in a statement posted on its Facebook page.
The strike on the army base will be regarded as a significant win for the Iran-backed group after weeks of setbacks following direct hits on the group's senior leaders, including former Secretary-General Hassan Nasrallah, in south Beirut.
A senior Hezbollah official told Al Jazeera network on Sunday following the attack that the group's capabilities are "still strong and capable of reaching Israel's rear".
The group issued a statement late on Sunday after the strike in which it threatened further attacks if Israel's Lebanon assault continued.
Hezbollah "promises the enemy that what it witnessed today in southern Haifa is nothing compared to what awaits it if it decides to continue its aggression against our... people," it said.
In what it described as a "complex" operation, the group said it had launched dozens of missiles towards Nahariya and Acre north of Haifa "with the goal of keeping Israeli defence systems busy".
At the same time, it launched "squadrons of various drones, some of which were being used for the first time, towards various areas in Acre and Haifa, where they were able to get past Israeli air defence radars without being detected" and hit the training camp in Binyamina south of Haifa, it added.
They "exploded in the rooms where dozens of officers and soldiers of the Israeli enemy were present".
After claiming the Binyamina attack, Hezbollah said it had launched missiles at a "maintenance and rehabilitation base" of the army, also south of Haifa.
Hezbollah has been fighting Israeli troops in the southern border areas for the past three weeks with clashes reportedly intensifying on Sunday. Some 25 Israelis were injured in close combat fighting, Hezbollah claimed.
There has been growing condemnation of Israel's actions in south Lebanon following repeated attacks on bases on UN peacekeepers stationed in the border zones. At least four UNIFIL troops have been injured in incidents connected to the Israeli army near the base in Naqoura.
Israeli Prime Minister Benjamin Netanyahu has called on UNIFIL to pull back from fighting zones despite this being in contradiction to its UN Security Council mandate. Several European nations, including France and Italy, on Friday condemned Israel's attacks on UNIFIL as violations of international law.
Earlier on Sunday, the US government announced it is sending a sophisticated air defence system to Israel to bolster its air defences against missile attacks.
The US Pentagon said it authorised the deployment of a Terminal High-Altitude Area Defense (THAAD) battery with a crew of US troops. The systems reportedly need 95 US troops to operate. The Pentagon did not reveal a timeline for its expected deployment in Israel.
As well as from Lebanon, Israel has been facing air incursions from the Iraqi Islamic Resistance groups and the Houthis in Yemen since Israel's war on Gaza began in October 2023 following Hamas' incursion on southern Israel.
The Iranian-backed Axis of Resistance groups have vowed to wage attacks against Israeli and US assets in the region in response to Israel's year-long war in Gaza.
(with Agencies)