The chief of Lebanese militant group Hezbollah says the wave of attacks on its communications network could be seen as a "declaration of war", vowing to deliver "just punishment" to Israel.
Hassan Nasrallah gave a televised address to respond to the sudden detonation of pagers and walkie-talkies across Lebanon this week. At the same time, Israel said it was striking Hezbollah targets in the country's south.
Nasrallah said the attacks on Hezbollah's communications systems "crossed all red lines" and would be met with "just punishment", but he did not elaborate.
"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," he said.
Lebanon's health ministry said the exploding devices killed 37 people and wounded about 3,000 others.
"The enemy went beyond all controls, laws and morals," he said, adding the attacks "could be considered war crimes or a declaration or war".
"They could be called anything and they deserve to be called anything. Of course, that was the intention of the enemy."
Hezbollah has blamed Israel for the attacks, but it has neither confirmed nor denied being behind them. Israeli jets created sonic booms over Beirut during the speech.
The Israeli military also said plans had been approved by its chief of staff for the area covering its northern border with Lebanon.
Israel's Defence Minister, Yoav Gallant, said late on Thursday, local time, that Israel would 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," he 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."
Nasrallah said Hezbollah would not stop fighting Israel on Lebanon's southern border until the war in Gaza ended.
Iranian state media reported that the head of Iran's Revolutionary Guards, Commander Hossein Salami, told Nasrallah that Israel would face "a crushing response from the axis of resistance".
World Health Organization Director-General Tedros Adhanom Ghebreyesus said the exploding devices "seriously disrupted Lebanon's already fragile health system".
He added that blood supplies and trauma kits had been distributed to the country.
The IDF confirmed that two soldiers were killed in Israel's north on Thursday, local time.
Israeli news outlets reported one was killed by a drone and the other by an anti-tank missile fired by Hezbollah across the border.
ABC/wires