Hand-held radios used by armed group Hezbollah have detonated across Lebanon's south in the country's deadliest day since cross-border fighting erupted between the militants and Israel nearly a year ago.
The blasts on Wednesday have stoked tensions after similar explosions of the group's pagers the day before.
Lebanon's health ministry said 20 people were killed and more than 450 injured on Wednesday in Beirut's suburbs and the Bekaa Valley, while the death toll from Tuesday's explosions rose to 12, including two children, with nearly 3000 injured.
Israeli officials have not commented on the blasts, but security sources said Israel's spy agency Mossad was responsible. One Hezbollah official said the episode was the biggest security breach in the group's history.
The exploding radios caused Lebanon's highest daily death toll since the October 7 attack. (AP PHOTO)
The operations, which appeared to throw Hezbollah into disarray, played out alongside Israel's 11-month-old war in Gaza and heightened fears of an escalation on its Lebanese border and the risk of a full-blown regional war.
"We are opening a new phase in the war. It requires courage, determination and perseverance from us," Israeli Defence Minister Yoav Gallant said in remarks at an air force base.
Jordan's Foreign Minister Ayman Safadi accused Israel of pushing the Middle East to the brink of a regional war by orchestrating a dangerous escalation on many fronts.
The US, which denied any involvement in the blasts, said it was pursuing intensive diplomacy to avert an escalation of the conflict. A US official, speaking on condition of anonymity, said Israel told Washington on Tuesday it was going to do something in Lebanon.
But Israel did not provide details and the operation itself was a surprise to Washington, the official said.
At least one of Wednesday's blasts in Lebanon took place near a funeral organised by Iran-backed Hezbollah for those killed the previous day when thousands of the group's pagers exploded across the country and wounded many of its fighters.
A Reuters reporter in the southern suburbs of Beirut said he saw Hezbollah members frantically taking batteries out of any walkie-talkies that had not exploded, tossing the parts in metal barrels. Hezbollah turned to pagers and other low-tech communication devices in an attempt to evade Israeli surveillance of mobile phones.
Lebanon's Red Cross said on social media platform X that it responded with 30 ambulance teams to multiple explosions in different areas, including the south of Lebanon and the Bekaa Valley.
Images of the exploded walkie-talkies showed labels bearing the name of Japanese radio communications and telephone company ICOM and resembled the firm's model IC-V82 device.
Tokyo Stock Exchange-listed ICOM said on Thursday it was investigating news reports two-way radio devices bearing its logo exploded in Lebanon and would release updated information as it becomes available on its website.
The company, which says it manufactures all of its radios in Japan, could not confirm whether it had shipped the device, in part because that model had been discontinued 10 years ago.
The Osaka-based firm said its products for overseas markets are sold exclusively through authorised distributors and it vets exports in accordance with Japan's security trade control regulations.
The company has previously warned about counterfeit versions of its devices circulating in the market, especially discontinued models.
The hand-held radios were purchased by Hezbollah five months ago, around the same time as the pagers, a security source said.
Hezbollah turned to low-tech communication devices to evade Israeli surveillance of mobile phones. (AP PHOTO)
In Tuesday's explosions, sources said Israeli spies remotely detonated explosives they planted in a Hezbollah order of 5000 pagers before they entered the country.
The United Nations Security Council will meet on Friday about the pager blasts after a request by Arab states.
Iran's envoy to the UN said in a letter on Wednesday that it "reserves its rights under international law to take required measures deemed necessary to respond" to the attack.
Hezbollah, which has vowed to retaliate against Israel, said on Wednesday it attacked Israeli artillery positions with rockets, the first strike at its arch-foe since the blasts.
The Israeli military said there were no reports of any damage or casualties.
The two sides have been fighting across the Lebanese border since the Gaza conflict erupted on October 7, 2023, fuelling fears of a wider Middle East war that could drag in the United States and Iran.
The previous highest daily Lebanese death toll was 11 who died in Israeli shelling in August, according to official counts.