By Laila Bassam and Maya Gebeily
BEIRUT/JERUSALEM (Reuters) - Deadly Israeli attacks that blew up Hezbollah radios and pagers crossed all red lines, the leader of the heavily armed Iran-backed Lebanese movement said on Thursday, as the United States called for restraint and urgent de-escalation.
Lebanon and Hezbollah have blamed Israel for attacks on Hezbollah's communications equipment that killed 37 people and wounded around 3,000, overwhelming Lebanese hospitals and wreaking bloody havoc on the militant group.
Israel has not directly commented on the attacks, which security sources say were probably carried out by its Mossad spy agency, which has a long history of carrying out sophisticated attacks on foreign soil.
"There is no doubt that we have been subjected to a major security and military blow that is unprecedented in the history of the resistance and unprecedented in the history of Lebanon," Hezbollah leader Hassan Nasrallah said in his TV address, filmed at an undisclosed location.
"This type of killing, targeting and crime may be unprecedented in the world," he said, appearing in front of a featureless red background in his customary black turban.
The attacks "crossed all red lines", he said. "The enemy went beyond all controls, laws and morals," he said, adding the attacks "could be considered war crimes or a declaration of war."
As the broadcast was aired, deafening sonic booms from Israeli warplanes shook Beirut, a sound that has become common in recent months but has taken on a greater significance as the threat of all-out war has steadily ramped up. Hezbollah reported that airstrikes resumed in the border area in the afternoon.
Israeli Defence Minister Yoav Gallant said late on Thursday that Israel will keep up military action against Hezbollah.
"In the new phase of the war there are significant opportunities but also significant risks. Hezbollah feels that it is being persecuted and the sequence of military actions will continue," Gallant said in a statement.
"Our goal is to ensure the safe return of Israel's northern communities to their homes. As time goes by, Hezbollah will pay an increasing price," Gallant said.
The Israeli military said late on Thursday it struck dozens of Hezbollah targets, including rocket launchers and weapon depots in southern Lebanon.
Prime Minister Benjamin Netanyahu convened his close circle of ministers for consultations, Israel's Channel 13 News reported.
"BIG HARSH BLOW"
Nasrallah said Hezbollah hoped Israeli troops would enter southern Lebanon because that would create a "historic opportunity" for the Iran-backed group.
No military escalation, killing, assassinations or all-out war would return Israeli residents to the border area, he added.
Whilst Nasrallah described the attacks as unprecedented, accusing Israel of trying to kill 5,000 people, he also played down the impact on Hezbollah, saying the group's structure had not been shaken.
"Yes, we received a big and harsh blow, but this is also the nature of war," Nasrallah said. "We know that our enemy has superiority on the technological level and we have never said otherwise."
Israel will face "a crushing response from the axis of resistance", Iran's Revolutionary Guards Commander Hossein Salami told Nasrallah on Thursday according to state media.
Speaking in Paris, U.S. Secretary of State Antony Blinken urged restraint, adding he did not want to see any escalatory actions by any party that make a Gaza ceasefire deal even more difficult.
The attacks on Hezbollah communications equipment sowed fear across Lebanon, with people abandoning electronic devices for fear of carrying bombs in their pockets.
ARMY DESTROYS PAGERS IN CONTROLLED BLASTS
Nasrallah said thousands of pagers had been targeted simultaneously, with some of the explosions happening in hospitals, pharmacies, markets, shops and streets busy with civilians, women and children. "With this operation, the enemy violated all laws and red lines," he said.
Hezbollah fired missiles at Israel on the day after the Oct. 7 cross-border attack by the Palestinian militant group Hamas which triggered the Gaza war, and since then constant exchanges of fire have occurred. Although neither side has allowed this to escalate into a full-scale war, it has led to the evacuation of tens of thousands of people from the border area on both sides.
"The Hezbollah terrorist organization has turned southern Lebanon into a combat zone. For decades, Hezbollah has weaponized civilian homes, dug tunnels beneath them, and used civilians as human shields," Israel's military said.
Hand-held radios used by Hezbollah detonated on Wednesday across Lebanon, killing 25 people and wounding hundreds.
The previous day, hundreds of pagers - used by Hezbollah to evade mobile phone surveillance - exploded at once, killing 12 people including at least two children, and injuring more than 2,300.
Lebanese Prime Minister Najib Mikati called on the United Nations Security Council to take a firm stand to stop what he called Israel's "aggression" and "technological war".
Israel says its conflict with Hezbollah, like its war in Gaza against Hamas, is part of a wider regional confrontation with Iran, which sponsors both groups as well as armed movements in Syria, Yemen and Iraq.
Also on Thursday, Israeli security forces said that an Israeli businessman had been arrested last month after attending at least two meetings in Iran where he discussed assassinating Prime Minister Benjamin Netanyahu, the defence minister or the head of the Shin Bet spy agency.
Israel has been accused of assassinations including a blast in Tehran that killed the leader of Hamas and another in a Beirut suburb that killed a senior Hezbollah commander within hours of each other in July.